Name the postulate or theorem you can use to prove the triangles congruent.

Step-by-step explanation:

According to the image, the given triangles have congruent hypothenuse and a corresponding congruent leg, that means we need to use Hypothenuse-Leg theorem.

The Hypothenuse-Leg (HL) theorem states that if the triangles have congruent hypothenuse and a corresponding congruent leg, then those triangles are congruent.

This theorem is based on the definition about the right angle of a right triangle, that's why is only needed to elements to have a congruence.

Therefore, the answer is HL theorem.

  21.3

step-by-step explanation:

multiplying the given equation by c/sin(25°), we get

  c = 9/sin(25°) ≈ 21.2958 ≈ 21.3

we assume "c" is the length of ab, the side opposite angle c in triangle abc.