These properties can then be used to find missing information about quadrilaterals.
Example 1

Example 2



ABCD is a rectangle. Find the size of the angles and sides marked by letters. Give reasons. 
ABCD is a parallelogram.

w + 50 = 90 (angles in a rectangle are 90°) z = 50° (alternate angles on parallel lines) x = 4 cm (opposite sides of rectangle are equal) y = 5 cm (opposite sides of rectangle are equal)

x = 5.7 cm (opposite sides of a parallelogram) a = 40° (opposite angles of parallelogram) b = 46° (alternate angles on paralllel lines)
