A semicircle is created when a lining passing v the center touches the two ends on the circle.

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In the listed below figure, the heat AC is dubbed the diameter that the circle. The diameter divides the circle right into two halves such the they room equal in area. These two halves are described as the semicircles. The area that a semicircle is fifty percent of the area that a circle.


A one is a locus of clues equidistant native a given suggest which is the center of the circle. The common distance indigenous the centre of a circle to its suggest is referred to as a radius.

Thus, the circle is entirely characterized by its centre (O) and radius (r).

Area the Semi Circle

The area of a semicircle is fifty percent of the area that the circle. As the area the a circle is πr2. So, the area that a semicircle is 1/2(πr2 ), wherein r is the radius. The value of π is 3.14 or 22/7.

Area the Semicircle = 1/2 (π r2)

Perimeter the Semicircle

The perimeter that a semicircle is the amount of the half of the circumference of the circle and diameter. Together the perimeter of a one is 2πr or πd. So, the perimeter the a semicircle is 1/2 (πd) + d or πr + 2r, where r is the radius.


The perimeter the Semicircle = (1/2) π d + d


Circumference = (πr + 2r)


Semi one Shape

When a one is cut into 2 halves or when the one of a circle is separated by 2, we get semicircular shape.

Since semicircle is fifty percent that the a circle, thus the area will certainly be half that that a circle.

The area of a circle is the variety of square systems inside the circle.


Let united state generate the over figure. This polygon have the right to be damaged into n isosceles triangle (equal sides being radius).

Thus, one together isosceles triangle can be represented as displayed below.


The area of this triangle is provided as ½(h*s)

Now because that n number of polygons, the area of a polygon is offered as


The ax n × s is equal to the perimeter that the polygon. As the polygon it s okay to look more and more like a circle, the value ideologies the one circumference, which is 2 × π × r. So, substituting 2×π×r for n × s.

Polygon area = h/2(2 × π × r)

Also, as the variety of sides increases, the triangle it s okay narrower and also so when s philosophies zero, h and r have the same length. So substituting r because that h:

Polygon area = h/2(2 × π × r)

= (2 × r × r × π)/2

Rearranging this we get

Area = πr2

Now the area of a semicircle is same to fifty percent of that of a full circle.


Area the a semicircle =(πr2)/2

Semi one Formula

The below table reflects the formulas associated with the semicircle the radius r.

Perimeter (Circumference)(½)πd + d; when diameter (d) is known
πr + 2r
Angle in a semicircle90 degrees, i.e. Appropriate angle
Central angle180 degrees

Semi one Examples

Example 1: 

Find the area the a semicircle the radius 28 cm.



Radius the semi circle = r = 28 cm

Area the semi one = (πr2)/2

= (½) × (22/7) × 28 × 28

= 1232

Therefore, the area that the semi circle is 1232 sq.cm.

Example 2: 

What is the perimeter of a semicircle through diameter 7 cm?



Diameter of semicircle = d = 7 cm

Formula because that the one (perimeter) of a semicircle using its diameter = (½)πd + d

Substitute the worth of d, we get;

= (½) × (22/7) × 7 + 7

= 11 + 7

= 18 

Therefore, the perimeter that the semicircle is 18 cm.

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Frequently Asked questions on Semicircle

Is a semicircle fifty percent the circle?

Yes, a semicircle is fifty percent the circle. The means, a circle can be separated into 2 semicircles.