Question 12
Four shaded right-angled triangles with leg lengths 1 cm × 4 cm, 2 cm × 4 cm, 3 cm × 4 cm, and 4 cm × 4 cm are fitted together to make a quadrilateral. This quadrilateral is then fit into a 5 cm × 8 cm rectangle. Find the area, in cm², of the quadrilateral that was formed (the shaded region). (Legs of a right-angled triangle are the sides beside the right angle)
