Question

The length of the hypotenuse line segment AC in right triangle ABC is 25cm the length of line segment BC is 15 cm

Answer 1

There isn't a question here. If you are finding AB, then the Pythagorean Theorem is the key.

$25^{2}$ = $15^{2}$ + $a^{2}$
625 = 225 + $a^{2}$
400 = $a^{2}$
20 = a