The correct answers are:
#1) When a pair of parallel lines are intersected by a third line, the same-side interior angles are supplementary.
#2) In an isosceles triangle, two of the angles are congruent.
Step-by-step explanation:
#1) When a pair of parallel lines is intersected by a third line (called a transversal), certain angles are congruent and certain angles are supplementary.
Some of the angles will be acute and some will be obtuse.
However, one thing that is always true is that same-side interior angles are supplementary.
#2) An isosceles triangle is defined as a triangle in which two sides are congruent. The angles formed by each of those two sides and the third side will be congruent as well, due to them being the same length.