Question

Both circles have the same center. The circumference of the inner circle is 25.12 millimeters.

What is the area of the shaded region?
4 mm
C=25.12 mm
Use 3.14 for . Write your answer as a whole number or a decimal rounded to the nearest
hundredth.

Answer 1

Explanation:

let r be radius of inner circle.

2πr=25.12

πr=25.12/2=12.56

3.14r=25.12

r=12.56/3.14=4

outer radius R=4+4=8 mm

reqd. area=πR²-πr²=π(R²-r²)=3.14(8²-4²)=3.14(64-16)=3.14×48= 150.72 mm²