PSLE In the figure, DEG and JHG are straight lines and HE is parallel to GF. ∠HJD is a right angle, ∠JDE = 51°, ∠DEF = 123° and ∠GHE = 70°.
- Find ∠DEH.
- Find ∠EFG.
(a)
∠DGJ
= 180° - 90° - 51°
= 39° (Angles sum of triangle)
∠GEH
= 180° - 70° - 39°
= 71° (Angles sum of triangle)
∠DEH
= 180° - 71°
= 123° (Angles on a straight line)
(b)
∠GEF
= 360° - 123° - 71° - 123°
= 43° (Angles at a point)
∠EFG
= 180° - 43° - 43°
= 94°
Answer(s): (a) 123°; (b) 94°