a Construct quadrilateral ABCD with D= 90°, |AD| = 6 cm, |DC| = 9 cm, |BC = 8.4 cm and |AB| = 5.4 cm. b Bisect angles D and A and let the bisectors meet at X. c Construct the perpendicular XP to DA. Draw the circle with centre X and radius |XP|. di Measure the radius of the cricle. ii Does the circle do anything special?