The figure is not drawn to scale. JK//ML and LK//NJ. Triangles JNK and KLM are isosceles triangles. Find
- ∠a
- ∠b.
(a)
∠KLM = ∠KJN = 74° (LK//NJ, KJ//LM)
∠JKN
= (180° - 74°) ÷ 2
= 106° ÷ 2
= 53° (Isosceles triangle)
∠LKM
= 180° - 74° - 74°
= 32° (Isosceles triangle)
∠a
= 180° - 74° - 53° - 32°
= 21° (Interior angles, KJ//LM)
(b)
∠b
= 180° - 25° - 21°
= 134° (Angles sum of triangle)
Answer(s): (a) 21°; (b) 134°
