Area of a Semi Circle Support Page

Welcome to our Area of a Semi Circle page.

Here you will find a range of free printable area sheets and support, which will help your child to learn to work out the area of different semi circles.

Area of a Semi-Circle

On this webpage you will find our range of worksheets to help your child learn to work out the area of a range of semi-circles.

These sheets are graded from easiest to hardest, and each sheet comes complete with answers.

Using these sheets will help your child to:

  • understand what area is;
  • know how to find the area of a range of semi-circles with either the diameter or radius given;
  • solve word problems involving area of semi-circles;

What is Area?

  • Area is a measure of the amount of space inside a shape.
  • It is measured in squares, so it can be square inches (in2), square cm (cm2), square feet(ft2), etc.

How to find the Area of a Semi Circle

A semi-circle is a half a circle. The area of a semi-circle is equal to half of the area of a circle with the same radius.

To find the area of a semi circle, follow these simple steps:

  • find the radius of the circle (the distance from one side to the center of the circle). It is the same as half of the diameter of the circle.
  • square the radius (multiply the radius by itself)
  • multiply this amount by pi (π)
  • halve this answer to find the area of the semi-circle
  • you have now found the area of the semicircle.
  • the formula for the circumference of a circle is A = ½ (π x r x r) or A = ½ (π r2), where A is the area and r is the radius of the circle.

Pi (written π) is a special mathematical number which is used to help calculate areas and perimeters of circles.

Pi always has the same value which is 3.141592...

Area of a Semi Circle Examples

Area of a Semi Circle Example 1

Find the area of the circle below to 1 decimal place.

semi circle area example 1

To find the area of the semi-circle, we need to square the radius first.

3 x 3 = 9.

Next we need to multiply this amount by pi (π).

9 x π = 9π

Finally we need to halve this amount.

½ x (9π) = 4.5 x π = 14.1 (to 1dp)

So the area of this semi-circle is 14.1 cm2.

Area of a Semi Circle Example 2

Find the area of the semi-circle below to the nearest square inch.

semi circle area example 2

To find the area of the semicircle, we need to square the radius first.

6 x 6 = 36

Next we need to multiply this amount by pi (π).

36 x π = 36π

Finally we need to halve this amount.

½ x (36π) = 18π = 56.5 (to 1dp)

So the area of this semi-circle is 57 in2 to the nearest square inch.

Area of a Semi Circle Example 3

Find the area of the semi-circle below and give your answer to the nearest whole number.

semi circle area example 3

To find the area of the semicircle, we need to find the radius first.

The radius is equal to half the diameter.

So the radius is half of 18 = 9 cm

Next we need to square the radius.

9 x 9 = 81

Next we need to multiply this amount by pi (π).

81 x π = 81π

Finally we need to halve this amount.

½ x (81π) = 40.5 x π = 127.2 (to 1dp)

So the area of this semi-circle is 127 cm2 to the nearest square cm.

Area of a Semi Circle Worksheets

Area of a Semi Circle Worksheets

Area of a Semi Circle Word Problems

  • Each worksheet comes with two versions: version A is in standard units, version B is in metric units.
  • Sheets 1A and 1B contain straightforward area word problems.

    Sheets 2A and 2B contain slightly harder word problems.

    More Recommended Math Worksheets

    Take a look at some more of our worksheets similar to these.

    More Circle Worksheets

    More Area Support and Resources

    We have a range of other area worksheets and support pages for a range of different 2d shapes.

    More Perimeter Worksheets

    Here is our selection of free printable perimeter worksheets for 3rd and up.

    Using these sheets will help your child to find the perimeter of a range of shapes including rectangles, rectilinear shapes, circles, quadrilaterals and regular shapes.

     

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