Circles

Concept

Semicircle

A semicircle is half of a circle. It is a two-dimensional figure obtained when a circle is cut into two halves. Its shape consists of an arc and a segment.

The radius of a semicircle is defined as the distance from the midpoint of the segment to any point of the arc.

The perimeter of a semicircle with radius r is the length of the segment plus half the circumference of a circle with radius r. The area of a semicircle with radius r is half the area of a circle with radius r.

Perimeter Area
P=2r + π r A=1/2π r^2
Exercises
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