Math CentralQuandaries & Queries


Question from Raraa, a student:

There are two identical circles . The edge of one circle is at the middle point of the other circle. There were overlapped . The area of the overlapped surface is 20000 square centimetres . How do I find the radius of the circle rounded to the nearest whole centimetre ?


I can help get you started.

Suppose the radius of each circle is r centimetres. Draw a diagram.


What do you know about the triangle ABC?
What is the measure of the angle ABC?
What is the area of the left circle?
The sector ABC is a fraction of the left circle. What fraction is this?
What is the area of the sector ABC?
What is the area of the triangle ABC?

I hope this helps,

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