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

• alt="" /> is a Radius of the Circle shown.

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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: alt="" />                    [Divide each side by 3.14.]
Step 4: 49 = r²                                        [Simplify.]
Step 5: alt="" />                                  [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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