Question

Please help me with this question!

Answer 1

Answer:

see explanation

Step-by-step explanation:

The sum of the 3 angles in a triangle = 180°, thus

∠1 = 180° - (72 + 57)° = 180° - 129° = 51°

The right angle at the left vertex is composed of 72° and ∠2, thus

∠2 = 90° - 72° = 18°

57° and ∠3 form a straight angle and are supplementary, thus

∠3 = 180° - 57° = 123°

∠4 = 180° - (∠2 + ∠3 ) ← sum of angles in a triangle

∠4 = 180° - (18 + 123)° = 180° - 141° = 39°