Since we’re given degrees, we will use the formula theta/ 360* pi*r^2
Lets try.
Our theta is the degree we’re given, which in this case is 120.
And our r(radius) is 9.
Now lets plug it all in.
A of Sector= 120/360* pi* 9^2
= 1/3* pi * 81
= 81 pi
3
= 27 pi yd^2