csat-suneung 2023 Q11

csat-suneung · South-Korea · csat__math 4 marks Sine and Cosine Rules Circumradius or incircle radius computation
As shown in the figure, quadrilateral ABCD is inscribed in a circle and $$\overline { \mathrm { AB } } = 5 , \overline { \mathrm { AC } } = 3 \sqrt { 5 } , \overline { \mathrm { AD } } = 7 , \angle \mathrm { BAC } = \angle \mathrm { CAD }$$ What is the radius of this circle? [4 points]
(1) $\frac { 5 \sqrt { 2 } } { 2 }$
(2) $\frac { 8 \sqrt { 5 } } { 5 }$
(3) $\frac { 5 \sqrt { 5 } } { 3 }$
(4) $\frac { 8 \sqrt { 2 } } { 3 }$
(5) $\frac { 9 \sqrt { 3 } } { 4 }$
As shown in the figure, quadrilateral ABCD is inscribed in a circle and
$$\overline { \mathrm { AB } } = 5 , \overline { \mathrm { AC } } = 3 \sqrt { 5 } , \overline { \mathrm { AD } } = 7 , \angle \mathrm { BAC } = \angle \mathrm { CAD }$$
What is the radius of this circle? [4 points]\\
(1) $\frac { 5 \sqrt { 2 } } { 2 }$\\
(2) $\frac { 8 \sqrt { 5 } } { 5 }$\\
(3) $\frac { 5 \sqrt { 5 } } { 3 }$\\
(4) $\frac { 8 \sqrt { 2 } } { 3 }$\\
(5) $\frac { 9 \sqrt { 3 } } { 4 }$