Question

If the area of a circle is equal to sum of areas of two circles with radii 3 and 4, radius of this circle is:

• A. 5
• B. 6
• C. 8
• D. 10

Answer 1

The correct option is A 5

Solution:
Let the radius of two circles be $r_1$ and $r_2$.
And radius of circle whose area is equal to sum of above two circles be $R$.
Hence,
$R^2=r_1^2+r_2^2$
$R^2=3^2+4^2$
$R=5$
So , the correct answer is option (a)