The sum of the two areas of two circles is the 80x square meters. Find the length of a radius of each circle of them is twice as
long as the other. What is the radius of the larger circle?
1 answer:
Answer:
--- small circle
--- big circle
Step-by-step explanation:
Given
-- sum of areas

Required
The radius of the larger circle
Area is calculated as;

For the smaller circle, we have:

For the big, we have

The sum of both is:


Substitute: 


Substitute 

Factorize
![80\pi = \pi[ r^2 + 4r^2]](https://tex.z-dn.net/?f=80%5Cpi%20%3D%20%5Cpi%5B%20r%5E2%20%2B%204r%5E2%5D)
![80\pi = \pi[ 5r^2]](https://tex.z-dn.net/?f=80%5Cpi%20%3D%20%5Cpi%5B%205r%5E2%5D)
Divide both sides by 

Divide both sides by 5

Take square roots of both sides


The radius of the larger circle is:



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Hope this helped
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