The figure is not drawn to scale. ACDE is a trapezium and AC // ED. Given that AE = AB, ∠EAB = 78° and ∠ACD = 103°.
- Find ∠CDE
- Find ∠ABE
- Find ∠BED
(a)
∠CDE
= 180° - 103°
= 77° (Interior angles, AC//ED)
(b)
∠ABE
= (180° - 78°) ÷ 2
= 102° ÷ 2
= 51° (Isosceles triangle)
(c)
∠BED
= ∠ABE
= 51° (Alternate angles, AC//ED)
Answer(s): (a) 77°; (b) 51°; (c) 51°