PSLE In the figure, KLMN is a parallelogram. HNK and JNM are straight lines and HJ = JK. ∠HJN = 21° and ∠LMN = 55°.
- Find ∠MNK.
- Find ∠NJK.
(a)
∠MNK
= 180° - 55°
= 125° (Interior angles)
(b)
∠HNJ
= ∠MNK
= 125° (Vertically opposite angles)
∠JHN
= 180° - 125° - 21°
= 34° (Angles sum of triangle)
∠JKN = ∠JHN (Isosceles triangle)
∠HJK
= 180° - 34° - 34°
= 112° (Angles sum of triangle)
∠NJK
= 112° - 21°
= 91°
Answer(s): (a) 125°; (b) 91°