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Radius
Definition of Radius

• Radius is the distance from the center of a circle or a sphere to any point on the circle or a sphere.
• In other words, radius is a line segment joining the center of a circle with any point  on the circle.

Examples of Radius

• is a radius of the circle shown.

Solved Example on Radius

Find the radius of a circle with area 153.86 square inches. Take π = 3.14
Choices:
A. 8
B. 7
C. 6
D. 5
Correct answer: C
Solution:
Step 1: Area of a circle of radius r = π r²                          [Original equation.]
Step 2: 153.86 = 3.14 r²                       [Substitute values.]
Step 3:                     [Divide each side by 3.14.]
Step 4: 49 = r²                                        [Simplify.]
Step 5:                                   [Evaluate square root on both sides.]
Step 6: r = 7                                      [Ignore the negative value.]

Related Terms for Radius

• Line Segment
• Center
• Circle
• Sphere

Additional Links for Radius

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