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Area of a Circle and its formulaPractice Problems & examples The area of a circle is all the space inside a circle's circumference.
Formula for Area of circle:The formula to find a circle's area : π×(radius)2 usually expressed as Πr2 where r is the radius of a circle. This page: Formula for area of circle Related Pages: Mixed Practice(area, circumference) | standard form equation for a circle |arc| chord |circumference | intersection of chords within circle In the picture on the left, the area of the circle is the part of the circle that is changing color. Example of Circle's Area
Since the radius of the circle on the left is 9", the area is Π(9")2 = 81Π square inches
≈254 square inches The area of the circle is the entire pink region.
Practice Problems
Problem 1)
What is the area of the circle on the left? Answer Remember the Formula: A= Π×radius2 A = (22')2 ×Π = 484Π square feet ≈ 1,520 square feet
Problem 2
What is this circle's area? Answer Remember the Formula: A= Π×radius2 A = (5")2 • Π = 25Π square inches ≈ 79 square inches
Problem 3
What is the area of a circle with a radius of 7 centimeters? Answer A = Π(7 centimeters)2 = 49 Π centimeters squared ≈ 153 square centimeters |