PSLE ABCD is a rhombus. DFB and DECG are straight lines.
- Find ∠ABD.
- Find ∠DCG.
- Find ∠DFE.
(a)
∠ABD
= (180° - 102°) ÷ 2
= 39° (Isosceles triangle)
(b)
∠BCD
= ∠BAD
= 102° (Rhombus)
∠DCG
= 180° - 102°
= 78° (Angles on a straight line)
(c)
∠EBF
= ∠ABF
= 39° (Rhombus)
∠BEF
= 180° - 70°
= 110° (Angles on a straight line)
∠DFE
= 39° + 110°
= 149° (Exterior angle of a triangle)
Answer(s): (a) 39° (b) 78° (c) 149°