Page 65 - Key Stage 3 Geometry

10. Draw lines between the left and right dots

and the midway intercept – you have your
concave quadrilateral.

11. Using your protractor, measure all four

internal angles.
12. Add all four angles, the result should be

o
360 .

4.3 Pentagon

The sum of the internal angles of a
o
pentagon is 540 . The following
exercise involves drawing an irregular
pentagon and then measuring all the

angles and adding up the result.

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