LFM Pure

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taiwan-gsat 2020 QB 6 marks Circle Equation Derivation View
Consider three distinct points $A$, $B$, $C$ in the coordinate plane, where point $A$ is $(1, 1)$. Circles are drawn with line segments $\overline{AB}$ and $\overline{AC}$ as diameters. These two circles intersect at point $A$ and point $P(4, 2)$. Given that $\overline{PB} = 3\sqrt{10}$ and point $B$ is in the fourth quadrant, the coordinates of point $B$ are ((12),(13)(14)).
taiwan-gsat 2021 QB 6 marks Chord Length and Chord Properties View
On the coordinate plane, a circle with radius 12 intersects the line $x + y = 0$ at two points, and the distance between these two points is 8. If this circle intersects the line $x + y = 24$ at points $P$ and $Q$, then the length of segment $\overline { P Q }$ is $\_\_\_\_$ (14)$\sqrt { (15) }$. (Express as a simplified radical)
taiwan-gsat 2021 Q6 5 marks Intersection of Circles or Circle with Conic View
On the coordinate plane, there is a regular hexagon $A B C D E F$ with side length 3, where $A ( 3,0 ) , D ( - 3,0 )$. How many intersection points does the ellipse $\frac { x ^ { 2 } } { 16 } + \frac { y ^ { 2 } } { 7 } = 1$ have with the regular hexagon $A B C D E F$?
(1) 0
(2) 2
(3) 4
(4) 6
(5) 8
taiwan-gsat 2021 Q8 5 marks Chord Length and Chord Properties View
As shown in the figure, $L$ is a line passing through the origin $O$ on the coordinate plane, $\Gamma$ is a circle centered at $O$, and $L$ and $\Gamma$ have one intersection point $A ( 3,4 )$. It is known that $B , C$ are two distinct points on $\Gamma$ satisfying $\overrightarrow { B C } = \overrightarrow { O A }$. Select the correct options.
(1) The other intersection point of $L$ and $\Gamma$ is $( - 4 , - 3 )$
(2) The slope of line $B C$ is $\frac { 3 } { 4 }$
(3) $\angle A O C = 60 ^ { \circ }$
(4) The area of $\triangle A B C$ is $\frac { 25 \sqrt { 3 } } { 2 }$
(5) $B$ and $C$ are in the same quadrant
taiwan-gsat 2022 Q5 8 marks Circle Identification and Classification View
On the coordinate plane, there is a figure $\Gamma$ with equation $(x-1)^2 + (y-1)^2 = 101$. Select the correct options.
(1) $\Gamma$ intersects the negative $x$-axis and negative $y$-axis at $(-9, 0)$ and $(0, -9)$ respectively
(2) The point on $\Gamma$ with the maximum $x$-coordinate is $(11, 0)$
(3) The maximum distance from a point on $\Gamma$ to the origin is $\sqrt{2} + \sqrt{101}$
(4) Points on $\Gamma$ in the third quadrant can be expressed in polar coordinates as $[9, \theta]$, where $\pi < \theta < \frac{3}{2}\pi$
(5) After a rotational linear transformation, the figure can still be expressed by a quadratic equation in two variables without an $xy$ term
taiwan-gsat 2022 Q14 5 marks Optimization on a Circle View
On a coordinate plane, there is a circle with radius 7 and center $O$. It is known that points $A, B$ are on the circle and $\overline{AB} = 8$. Then the dot product $\overrightarrow{OA} \cdot \overrightarrow{OB} =$ (14--1) (14--2).
taiwan-gsat 2022 Q18 3 marks Area and Geometric Measurement Involving Circles View
On the coordinate plane, there is an annular region formed by the intersection of the exterior of the circle $x ^ { 2 } + y ^ { 2 } = 3$ and the interior of the circle $x ^ { 2 } + y ^ { 2 } = 4$ . A person wants to use a straight scanning rod of length 1 to scan a certain region $R$ above the $x$-axis of this annular region. He designs the scanning rod with black and white ends moving respectively on the semicircles $C _ { 1 } : x ^ { 2 } + y ^ { 2 } = 3 ( y \geq 0 )$ and $C _ { 2 } : x ^ { 2 } + y ^ { 2 } = 4 ( y \geq 0 )$ . Initially, the black end of the scanning rod is at point $A ( \sqrt { 3 } , 0 )$ and the white end is at point $B$ on $C _ { 2 }$ . Then the black and white ends move counterclockwise along $C _ { 1 }$ and $C _ { 2 }$ respectively until the white end reaches point $B ^ { \prime } ( - 2,0 )$ on $C _ { 2 }$ , at which point scanning stops.
What are the coordinates of point $B$? (Single-choice question, 3 points)
(1) $( 0,2 )$
(2) $( 1 , \sqrt { 3 } )$
(3) $( \sqrt { 2 } , \sqrt { 2 } )$
(4) $( \sqrt { 3 } , 1 )$
(5) $( 2,0 )$
taiwan-gsat 2023 Q11 5 marks Circles Tangent to Each Other or to Axes View
On a coordinate plane, there is a circle with center $A(a, b)$ that is tangent to both coordinate axes. There is also a point $P(c, c)$, where $a > c > 0$, and it is known that $\overline{PA} = a + c$. Select the correct options.
(1) $a = b$ (2) Point $P$ is on the line $x + y = 0$ (3) Point $P$ is inside the circle (4) $\frac{a + c}{b - c} = \sqrt{2}$ (5) $\frac{a}{c} = 2 + 3\sqrt{2}$
taiwan-gsat 2024 Q10 6 marks Chord Length and Chord Properties View
On the coordinate plane, let $\Gamma$ be a circle with center at the origin, and $P$ be one of the intersection points of $\Gamma$ and the $x$-axis. It is known that the line passing through $P$ with slope $\frac{1}{2}$ intersects $\Gamma$ at another point $Q$, and $\overline{PQ} = 1$. Then the radius of $\Gamma$ is . (Express as a simplified radical)
taiwan-gsat 2024 Q10 5 marks Area and Geometric Measurement Involving Circles View
On the coordinate plane, there is a square and a regular hexagon, with the square to the right of the hexagon. Both regular polygons have one side on the $x$-axis, and the center $A$ of the square and the center $B$ of the hexagon are both above the $x$-axis. The two polygons have exactly one intersection point $P$. The side length of the square is 6, and the distance from point $P$ to the $x$-axis is $2\sqrt{3}$. Select the correct options.
(1) The distance from point $A$ to the $x$-axis is greater than the distance from point $B$ to the $x$-axis
(2) The side length of the regular hexagon is 6
(3) $\overrightarrow{BA} = (7, 3 - 2\sqrt{3})$
(4) $\overline{AP} > \sqrt{10}$
(5) The slope of line $AP$ is greater than $-\frac{1}{\sqrt{3}}$
taiwan-gsat 2024 Q16 5 marks Sphere and 3D Circle Problems View
In a spatial coordinate system, there is a globe with center at $O ( 0,0,0 )$ and north pole at $N ( 0,0,2 )$. A point $A$ on the sphere has coordinates $\left( \frac { \sqrt { 3 } } { 2 } , \frac { 1 } { 2 } , \sqrt { 3 } \right)$. The point on the equator farthest from point $A$ is point $P$. On the great circle passing through points $A$ and $P$, the length of the minor arc between these two points is (blank). (Express as a fraction in lowest terms)
taiwan-gsat 2025 Q2 5 marks Circle Identification and Classification View
On the coordinate plane, which of the following equations represents a circle passing through the point $(1,1)$?
(1) $( x - 1 ) ^ { 2 } + y ^ { 2 } = 1$
(2) $( x - 1 ) ^ { 2 } + ( y - 1 ) ^ { 2 } = 1$
(3) $3 ( x - 1 ) ^ { 2 } + y ^ { 2 } = 1$
(4) $x ^ { 2 } + y ^ { 2 } = 1$
(5) $x ^ { 2 } + 3 y = 4$
taiwan-gsat 2025 Q11 6 marks Area and Geometric Measurement Involving Circles View
On the coordinate plane, there is a parallelogram $\Gamma$, where two sides lie on lines parallel to $5x - y = 0$, and the other two sides lie on lines perpendicular to $3x - 2y = 0$. Let $Q$ be the intersection point of the two diagonals of $\Gamma$. It is known that $\Gamma$ has a vertex $P$ satisfying $\overrightarrow{PQ} = (10, -1)$. The area of $\Gamma$ is (11--1)(11--2)(11--3).
taiwan-gsat 2025 Q16 5 marks Chord Length and Chord Properties View
On the coordinate plane, let $L _ { 1 }$ and $L _ { 2 }$ be two lines passing through point $(3, 1)$ with slopes $m$ and $- m$ respectively, where $m$ is a real number. Let $\Gamma$ be a circle with center at the origin. Given that $\Gamma$ intersects $L _ { 1 }$ at two distinct points $A$ and $B$, and the distance from the center to $L _ { 1 }$ is 1, and $\Gamma$ is tangent to $L _ { 2 }$, then the length of chord $\overline { A B }$ is (express as a fraction in lowest terms).
turkey-yks 2011 Q38 Intersection of Circles or Circle with Conic View
$$|\mathrm{OM}| = 2 \text{ units}$$
In the rectangular coordinate plane, a semicircle with center at point M and a quarter circle with center at the origin intersect at point A as shown in the figure.
Accordingly, what is the x-coordinate of point A?
A) $\frac{5}{3}$ B) $\sqrt{2}$ C) $\frac{\sqrt{3}}{2}$ D) $\frac{3}{2}$ E) $\sqrt{3}$
turkey-yks 2012 Q34 Area and Geometric Measurement Involving Circles View
The figure below shows the construction used to obtain a square with an area equal to that of a given rectangle.
ABCD is a rectangle, HDFG is a square, semicircle with center O
$$A ( ABCD ) = A ( HDFG )$$
The F vertex of the square HDFG in the figure lies on the semicircle with center O.
Given that the perimeter of rectangle ABCD is 36 cm, what is the diameter of the circle in cm?
A) 12
B) 15
C) 18
D) 21
E) 24
turkey-yks 2013 Q36 Tangent Lines and Tangent Lengths View
The method of drawing a tangent to a circle with center O from an external point P is given below.
  • Line segment OP is drawn.
  • The midpoint M of line segment OP is determined.
  • A circle with center M and diameter [OP] is drawn.
  • The intersection points of the circles with centers O and M are marked. Let one of these points be T.
  • Ray [PT is tangent to the circle with center O at point T.

In this construction, if the radii of the circles with centers O and M are 4 cm and 3 cm respectively, what is the length $| PT |$ in cm?
A) $3 \sqrt { 3 }$
B) $2 \sqrt { 5 }$
C) $\sqrt { 7 }$
turkey-yks 2013 Q38 Chord Length and Chord Properties View
$ABCDEF$ is a regular hexagon $|AL| = |LB|$ $| \mathrm { BC } | = 4 \mathrm {~cm}$ $| \mathrm { DK } | = 3 \mathrm {~cm}$ $|KE| = \mathrm { x }$ According to the given information above, what is x in cm?
A) $4 \sqrt { 3 }$
B) $3 \sqrt { 5 }$
C) $3 \sqrt { 7 }$
D) 6
E) 7
turkey-yks 2014 Q33 Area and Geometric Measurement Involving Circles View
The following information is known about points A, B, C, D, and E in the plane.
$$\begin{aligned} & { [ A B ] \perp [ B C ] } \\ & { [ A B ] \cap [ C D ] = E } \\ & | A E | = | B C | = 4 \text { units } \\ & | A B | = | C D | = 7 \text { units } \end{aligned}$$
Given this, what is the length |DE| in units?
A) $\sqrt { 3 }$
B) $\sqrt { 5 }$
C) $\sqrt { 7 }$
D) 2
E) 3
turkey-yks 2014 Q35 Area and Geometric Measurement Involving Circles View
ABCD is a square $\mathrm { AF } \perp \mathrm { FB }$ $\mathrm { DE } \perp \mathrm { AF }$ $| E F | = 4 \mathrm {~cm}$
Given that the area of triangle AFB in the figure is $30 \mathrm {~cm} ^ { 2 }$, what is the area of square ABCD in $\mathrm { cm } ^ { 2 }$?
A) 81
B) 100
C) 120
D) 136
E) 144
turkey-yks 2015 Q35 Circles Tangent to Each Other or to Axes View
Below, two concentric circles with center $O$ and a circle with center $M$ tangent to both circles are given.
The radius of the small circle with center $O$ is 4 units less than the radius of the large circle with center $O$, and 1 unit more than the radius of the circle with center $M$.
Accordingly, what is the area of the shaded region in square units?
A) $28 \pi$ B) $32 \pi$ C) $36 \pi$ D) $39 \pi$ E) $45 \pi$
turkey-yks 2017 Q31 Area and Geometric Measurement Involving Circles View
Teacher Aslı created the number 3 on a piece of paper by painting identical equilateral triangles inside an equilateral triangle ABC as shown in the figure.
If the area of equilateral triangle ABC is 96 square units, what is the painted area in square units?
A) 22 B) 27 C) 33 D) 36 E) 44
turkey-yks 2017 Q32 Area and Geometric Measurement Involving Circles View
Given two squares as shown; the area of square ABCD is equal to 2 times the area of square CEFG.
Accordingly, what is the ratio $\frac { | \mathrm { AF } | } { | \mathrm { AG } | }$?
A) $\frac { \sqrt { 5 } } { 2 }$ B) $\frac { 2 \sqrt { 2 } } { 3 }$ C) $\frac { \sqrt { 10 } } { 3 }$ D) $\frac { 2 \sqrt { 2 } } { 5 }$ E) $\frac { \sqrt { 10 } } { 5 }$
turkey-yks 2017 Q33 Area and Geometric Measurement Involving Circles View
A rectangle ABCD with short side 12 units and long side 18 units is folded along AL and KC such that $| \mathrm { KB } | = | \mathrm { LD } | = 4$ units. Then, with M and N being the midpoints of the sides they are on, this resulting shape is folded again along the line MN as shown to form a trapezoid.
Accordingly, what is the area of this trapezoid in square units?
A) 108 B) 105 C) 102 D) 99 E) 96
turkey-yks 2017 Q34 Chord Length and Chord Properties View
$ABCDEF$ is a regular hexagon $\mathrm { K } , \mathrm { L } \in [ \mathrm { AD } ]$ $| \mathrm { AB } | = 6$ units $| \mathrm { KL } | = \mathrm { x }$
In the figure, points $K$ and $L$ are on semicircles with diameters $AB$ and $DE$ respectively.
Accordingly, what is $x$ in units?
A) 5 B) 6 C) 9 D) $3 \sqrt { 3 }$ E) $6 \sqrt { 3 }$