Question

The sum of the areas of two circles is 770 sq. cm and radius of one of them is 14 cm. Find the radius of the other circle

Answer 1

Let the radius of the other circle be r.
Area of the circle, which is sum of the areas of circles of radius $14$ and r $=770$
$\frac{22}{7}\times {14}^2+\frac{22}{7}\times r^2=770$
$\frac{22}{7}\times (196+r^2)=770$
On simplifying, $r^2=49=>r=7$
Thus, radius of the other circle is $7$ cm.