Question

A triangle is shown with its exterior angles. The interior angles of the triangle are angles 2, 3, 5. The exterior angle at angle 2 is angle 1. The exterior angle at angle 3 is angle 4. The exterior angle at angle 5 is angle 6.
Which statements are always true regarding the diagram? Select three options.

m∠5 + m∠3 = m∠4
m∠3 + m∠4 + m∠5 = 180°
m∠5 + m∠6 =180°
m∠2 + m∠3 = m∠6
m∠2 + m∠3 + m∠5 = 180°

Answer 1

Correct choices:
- m∠5 + m∠6 = 180° (∠6 is the exterior at vertex 5, so it is supplementary to interior ∠5)
- m∠2 + m∠3 = m∠6 (an exterior angle equals the sum of the two remote interior angles)
- m∠2 + m∠3 + m∠5 = 180° (sum of the interior angles of a triangle)

The other two statements are not always true.