2 The diagram shows a triangle \(A B C\).
The size of angle \(B A C\) is \(72 ^ { \circ }\) and the size of angle \(A B C\) is \(48 ^ { \circ }\). The length of \(B C\) is 20 cm .
- Show that the length of \(A C\) is 15.6 cm , correct to three significant figures.
- The midpoint of \(B C\) is \(M\). Calculate the length of \(A M\), giving your answer, in cm , to three significant figures.
[0pt]
[4 marks]