PSLE In the figure, FGHJ is a parallelogram. DJF and EJH are straight lines and DE = EF. ∠DEJ = 25° and ∠GHJ = 57°.
- Find ∠HJF.
- Find ∠JEF.
(a)
∠HJF
= 180° - 57°
= 123° (Interior angles)
(b)
∠DJE
= ∠HJF
= 123° (Vertically opposite angles)
∠EDJ
= 180° - 123° - 25°
= 32° (Angles sum of triangle)
∠EFJ = ∠EDJ (Isosceles triangle)
∠DEF
= 180° - 32° - 32°
= 116° (Angles sum of triangle)
∠JEF
= 116° - 25°
= 91°
Answer(s): (a) 123°; (b) 91°