Question

Please check my work!

Answer 1

Let's call the 3 areas from left to right as A1,A2,A3 and the overall area as A.
Such that A1+A2+A3 = A.
You need to solve for A3.
A1 is simply a quarter of a circle and A2 is a right angled triangle.
I suppose you know the formulae's for both A1 and A2.

Answer 2

if I draw AD line, then ADO İS equilateral triangle. m(DOA)=60. Area of half circle is 2pi. Colored area= 2pi.120/360=2pi/3 but answer is 4pi/3 tell me where i'm wrong.

Answer 3

If area of full circle is 4pi

then area of 120 degree sector would be 4pi*120/360

Answer 4

so we need to consider the who circle again thank you :)

Answer 5

Btw, brilliant job in finding that ADO is equilateral !