Question

Triangle ABC is congruent to triangle DEF. In triangle ABC, side AB measures 9, side BC measures 3x+1, and side CA measures 7. In triangle DEF, side DE measures 9, side EF measures 2x+2, and side FD measures 7. What equation would help you to solve for the side length of BC and EF? Explain your reasoning using complete sentences.

Answer 1

If those triangles are congruent than measures of the sides of ABC and DEF are equal:
AB = DE = 9;
AC = DF = 7
and : BC = EF
The equation is : 3 x + 1 = 2 x + 2
3 x - 2 x = 2 - 1
x = 1
BC = EF = 4