Answer:
a ≈ 21.8
Step-by-step explanation:
We require the third angle in the triangle
Subtract the sum of the 2 angles from 180
third angle = 180° - (75 + 31.8)° = 180° - 106.8° = 73.2°
Using the Sine rule, that is
=
( cross- multiply )
a × sin75° = 22 × sin73.2° ( divide both sides by sin75° )
a = ≈ 21.8 ( to the nearest tenth )