Question

Find the unknown marked angles in the given figure:

Answer 1

We know that in a triangle if one side of it is produced, then

Exterior angle = sum of its interior opposite angles.

In fig.,

105° = b + b

⇒ 2b = 105°

⇒ b =`(105°)/2=52.5°`

But a + 105° = 180° ........(Linear pair)

⇒ a = 180° − 105° = 75°

Hence a = 75°, b = 52.5°