A student wants to prove that the base angles of an isosceles triangle are congruent. The student draws isosceles triangle ABC with base angles B and C, as shown below. Point M is drawn as the midpoint of segment BC. Which of the following could be used as part of the proof that angle B is congruent to angle C? Select all that apply.
1) angle B is congruent to angle C because corresponding parts of congruent triangles are congruent.
2) AM is congruent to AM because of the symmetric property.
3) AB is congruent to AC because of the definition of an isosceles triangle.
4) BM is congruent to CM because of the definition of a midpoint.
5) ΔABC is congruent to ΔACB because of the SAS triangle congruence criterion.
