What is the area of the circle whose radius is the average of the radii of two circles with areas of `16pi and 100pi`?

What is the radius of a circle whose area is equal to the sum of the area of two circles whose radii are 20 cm and 21 cm .

What is the radius of a circle with an area of (pi)/(4) ?

What is the diameter of a circle whose area is equal to the sum of the areas of two circles of radii 40 cm and 9 cm ?

What is the radius of a circle whose circumference is pi ?

Find the area of a circle whose circumference is 8pi

Find the diameter of the circle whose area is equal to the sum of the areas of two circles having radii 4 cm and 3 cm.

The radii of the two circles are 4 cm and 3 cm . Find the radius of the circle whose area is equal to the sum of the areas of the two circles . Also , find the circumference of the circle .

If the ratio of the areas of two circles is 9:16, find the ratio of their radii.

What is the area of circle with a circumference of 10pi ?