One diagonal of a cyclic quadrilateral coincides with a diameter of a circle whose area is 36$\pi$ $cm^2$. If the other diagonal which measures 8 $cm$ meets the first diagonal at right angles, find the area of the quadrilater.
So I derived the area given for the circle and got Radius = $6$ I got stuck computing the area even though I know the two diagonals which is 12 cm and 8 cm I know that $ac+bd=d_1d_2$ I was thinking of using the $A=\sqrt{(s-a)(s-b)(s-c)(s-d)}$ by Brahmagupta's but how? Idk the sides..
Best Answer
Hint: The quadrilateral is a kite.
The area of a kite is simply the product of the lengths of the two diagonals, divided by two (why?).