In the figure, the area of the shaded region is 243π cm2.
What is the value of x?

Answer
Find out the value of x.
To proof
Formula
[tex]Area\ of\ circle = \pi r^{2}[/tex]
As given
Radius of the bigger circle = 18cm
Radius of the smaller circle =x
As shown in the diagram
shaded area = Area of the bigger circle - Area of the smaller circle
than we have
[tex]243 \pi = \pi\ (18\times18 - x^{2} )[/tex]
[tex]cancelled\ the\ pi\ value\ on\ both\ side[/tex]
243 = 324 - x²
324- 243 = x²
√81 = x
9cm = x
the value of x is 9cm .
Hence proved