Respuesta :

Answer:

CD = 7

Step-by-step explanation:

Given that the triangles are congruent, then corresponding sides are congruent, that is

CD = AB , substitute values

3y + 1 = 15 - 4y ( add 4y to both sides )

7y + 1 = 15 ( subtract 1 from both sides )

7y = 14 ( divide both sides by 7 )

y = 2

Thus

CD = 3y + 1 = 3(2) + 1 = 6 + 1 = 7