Question

The radii of two circles are $8$cm and $6$cm respectively. Find the radius of the circle having its area equal to the sum of the areas of the two circles.

• A. $32cm$
• B. $23cm$
• C. $15cm$
• D. $10cm$

Answer 1

The correct option is D $10cm$

Let the radius of required circle is $r$ cm.
So, $\pi r^2=\pi r_1^2+\pi r_2^2$
$r^2=r_1^2+r_2^2$
$r^2=(8{)}^2+(6{)}^2$
$r^2=100$
$r=10cm$