$$\(A B C D E\)$$ is a pentagon. Explain why the diagram shows that the sum of the interior angles of a pentagon is $$\(540^{\circ}\)$$. Do not measure any angles.

C6.1 Interpret and use three-figure bearings. (Measured clockwise from the North, i.e. 000°–360°.)

C6.2 Apply Pythagoras’ theorem and the sine, cosine and tangent ratios for acute angles to the calculation of a side or of an angle of a right- angled triangle. (Angles will be quoted in degrees. Answers should be written in degrees and decimals to one decimal place.)

C6.3 Extended curriculum only.

C6.4 Extended curriculum only.

C6.5 Extended curriculum only.