
Answer:
The Three options are
1.  m∠5 + m∠6 = 180°  ...........Linear Pair
2. ∠2+ ∠3 = ∠6.................Exterior angle Property of Triangle
3. m∠2 + m∠3 + m∠5 = 180° .....Triangle Sum Property
Step-by-step explanation:
Consider Δ ABC with Exterior angles as
∠1 , ∠4 ,and ∠6
Exterior angle Property of Triangle:
An exterior angle of a triangle is equal to the sum of the opposite interior angles.
For Exterior ∠1 we have
∠1 = ∠5 + ∠3 .................Exterior angle Property of Triangle
Similarly,
For Exterior ∠4 we have
∠4 = ∠5 + ∠2.................Exterior angle Property of Triangle
Similarly,
For Exterior ∠6 we have
∠6 = ∠2 + ∠3.................Exterior angle Property of Triangle
Triangle Sum Property:
Ina triangle sum of the measures of angles is equal to 180°
∴ m∠2 + m∠3 + m∠5 = 180° .....Triangle Sum Property
Linear Pair:
The measure of a straight angle is 180 degrees, so a linear pair of angles must add up to 180 degrees.
∴ m∠5 + m∠6 = 180°  ...........Linear Pair