Question

If the radii of two concentric circles are 15 cm and 13 cm, respectively, then the area of the circular ring in sq. cm will be

• A. 176 sq.cm
• B. 178 sq.cm
• C. 180 sq.cm
• D. 200 sq.cm

Answer 1

The correct option is A 176 sq.cm

The radii of the larger circle R =15 cm and the smaller circler =13 cm.

Area of the circular ring =$\pi (R^2-r^2)$
$=\pi (R+r)(R-r)=\frac{22}{7}(15+13)\times (15-13)=\frac{22}{7}\times 28\times 2=176sq.cm$