Question

In the following figure the diameter of the inner circle is 3 m and that of outer circle is 11 m. Taking π to be `22/7`, find the area of the shaded region.

Answer 1

Given: Inner circle diameter = 3 m, outer circle diameter = 11 m; take π = `22/7`.

Step-wise calculation:

1. Radius of inner circle r = `3/2` = 1.5 m.

2. Radius of outer circle R = `11/2` = 5.5 m.

3. Area of shaded region (annulus) = π(R² – r²).

4. R² = 5.5²

= 30.25

r² = 1.5²

= 2.25

5. R² – r² = 28.0

6. Area = `22/7 xx 28` 

= 22 × 4

= 88 m²

Area of the shaded region = 88 m².