The proof that is shown. Select the answer that best completes the proof. Given: MNQ is isosceles with base , and and bisect each other at S. Prove: Square M N Q R is shown with point S in the middle. Lines are drawn from each point of the square to point S to form 4 triangles. We know that MNQ is isosceles with base . So, by the definition of isosceles triangle. The base angles of the isosceles triangle, and , are congruent by the isosceles triangle theorem. It is also given that and bisect each other at S. Segments _______ are therefore congruent by the definition of bisector. Thus, by SAS. NS and QS NS and RS MS and RS MS and QS