What you need: ruler, protractor, pencil and paper. Use these to construct a triangle when you know the length of 1 side and the 2 angles at each end of it. In this case use the length 8 cm, and ...

STEP 2: Centre the protractor on the same end of the line and make a dot at 40°. From the same end, use a ruler to draw a line through the dot, crossing the arc.