The radius of the circle is 7cm determine the radius of another circle whose area is 9 times of first circle
Answers
Step-by-step explanation:
Radius of first circle = 7cm
area of second circle = 9 (area of first circle)
πr2= 9(π×7×7)
r2 = 9×7×7
r2 = 441
r = 21 Ans.
Concept:
Circle is a figure with no edges and vertices. It has a center and a radius.
It is the curve traced out by a point that moves in a plane so that its distance from a given point is constant.
Given:
We are given that:
The radius of first circle is 7 cm.
The area of other circle is 9 times the area of the first circle.
Find:
We need to find the radius of the other circle.
Solution:
First we will calculate the area of the first circle:
Area=πr²
A=π(7cm)²
A=49π cm²
Now we know that:
Area of other circle (A')=9A
A'=9(49π cm²)
π(R)²=9×49×π cm²
R²=441 cm²
R=21 cm
Therefore, the radius of another circle is equal to 21 cm.
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