A body of mass 5 kg moving with a uniform speed $3 \sqrt { 2 } \mathrm {~m} \mathrm {~s} ^ { - 1 }$ in $X - Y$ plane along the line $y = x + 4$. The angular momentum of the particle about the origin will be $\_\_\_\_$ $\mathrm { kg } \mathrm { m } ^ { 2 } \mathrm {~s} ^ { - 1 }$.