The sum of the areas of two circles is 80 square meters. Find the length of a radius of each circle if one of them is twice as long as the other.

Question

Mathematics

Cherish Dawson

21 January, 12:25

The sum of the areas of two circles is 80 square meters. Find the length of a radius of each circle if one of them is twice as long as the other.

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Claudia · Answer 1

The area of a circle is given or expressed as:

A = (pi) r^2

The sum of the areas of two circles is 80 square meters.

A1 + A2 = 80

(pi) r1^2 + (pi) r2^2 = 80

where r1 = 2r2

(pi) 2r2^2 + (pi) r2^2 = 80

r2 = 2.91

r1 = 5.83