A circle with the radius of 6 sits inside a circle of 9. What is the area of the shaded region?

Equation for the area of a circle- π r² 
The 2 radiuses are 6 and 9. 
6 squared is 36 and 9 squared is 81. 
The smaller one is 36π and the larger one is 81π. 
The difference between them is the area of the shaded region. 
81π - 36π = 45π 
Use 3.14 for π. 
45 x 3.14 = 141.3 u² 
Hope this helps!