Answer:



Explanation:
Statement 2
As the interior angles of a triangle sum to 180°, then for the given triangle we can say that:

From inspection of the given triangle, m∠A = 60° and m∠C = 40°.
Substitute these angles into the equation from statement 1 and solve for m∠1:




Therefore, the measure of angle 1 is 80°.

Statement 4
A linear pair is two angles which when combined together form a straight line. Therefore, the angle measures of a linear pair sum to 180°.
As ∠1 and ∠2 form a linear pair, we can say that:

Substitute the found value of m∠1 and solve for m∠2:



Therefore, the measure of angle 2 is 100°.

The conclusion is only true for this specific triangle, since the angles of other triangles could be labelled in a different way.
For example, ∠A in this triangle could be labelled as ∠B in another triangle, which would mean that this specific conclusion would not hold true.