Question

The radii of the two circles are 4 cm and 3 cm respectively. The diameter of the circle having an area equal to the sum of the areas of the two circles (in cm) is ____________.

Options

• 5

• 7

• 10

• 14

Answer 1

The radii of the two circles are 4 cm and 3 cm respectively. The diameter of the circle having an area equal to the sum of the areas of the two circles (in cm) is 10.

Explanation:

`pi "R"^2 = pi "r"_1^2 + pi "r"_2^2`

`= pi ["r"_1^2 + r_2^2]= pi [4^2 + 3^2]`

`=> "R"^2 = 25 => "R" = 5  "cm"`

d = 5 x 2 = 10 cm