In the figure, GKNR is a rectangle, NPRS is a rhombus and KLMN is a parallelogram. ∠NPR = 78° and ∠MNP = 91°.
- Find ∠JNK
- Find ∠NML
(a)
∠RSN = ∠RPN = 78°
∠SNR
= (180° - 78°) ÷ 2
= 102° ÷ 2
= 51° (Isosceles triangle)
∠JNK
= 90° - 51°
= 39°
(b)
∠KNM
= 360° - 91° - 90° - 51°
= 128° (Angles at a point)
∠LMN
= 180° - 128°
= 52° (Interior Angles, KN//LF)
Answer(s): (a) 39°; (b) 52°