  # Find Compound Perimeters

In this worksheet, students will find the perimeter of compound shapes including circles. Key stage:  KS 4

GCSE Subjects:   Maths

GCSE Boards:   OCR, AQA, Eduqas, Pearson Edexcel,

Curriculum topic:   Mensuration, Geometry and Measures

Curriculum subtopic:   Perimeter Calculations Mensuration and Calculation

Difficulty level:   #### Worksheet Overview Question

Why was the Area upset with the Perimeter?

Because the area thought the perimeter always went around the problem.

Perimeter is the total distance taken up around the outside of a shape.

Can you think of examples of where perimeter may be used?

A good example is if you are fencing a field, or building a wall around something.  You will need to know the perimeter.

To find the perimeter

Just add up the lengths of each shape.

Example 1  When you have a missing length such as in this example, break it down as shown above.

Perimeter = 10 + 2 + 6 + 6 + 4 + 8 = 36 cm.

Example 2  Calculate the missing length.  If the slant height isn't given you have to assume the slant height is 4 cm.

Perimeter = 4 + 10 + 10 = 24 cm

Example 3 The missing side length is 11 cm and the length of the semi circle can be calculated by finding the circumference and dividing by 2.

Circumference = π x diameter

The missing length of the rectangle is 11 cm.

The circumference of the circle is π x 12 = 37.70 cm

12 + 11 + 11 + 37.70 cm = 71.70 cm

Lets get around these problems.

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