With this show work plz explain answer should be a=. cm squared

The shaded region is actually a sector and the formula for the area of a sector is:
central angle/360 x pi x radius squared, which is basically a fraction of the area of the circle. With this basic background knowledge, all we have to do is substitute the values into the formula.

(80/36) x pi x 81
= 80/4 x pi x 9
= 720/4 x pi
= 180pi cm squared.

The 3rd quadrant as 3x+g5ti=56i: 92d-543