The length of the hypotenuse, line segment ac, in right triangle abc is 25 cm. the length of line segment bc is 15 cm.

I guess the question is to find the length of AB.
ABC is a right triangle, and AC is its hypotenuse. AC = 25cm, and BC = 15 cm.
Based on Pythagoras' theorem, AC^2 = AB^2 + BC^2
25^2 = AB^2 + 15^2
625 = AB^2 + 225
AB^2 = 400
So AB = √400 = 20

So the length of AB is 20 cm.

Hope this Helps! :)

One unique triangle, because those angles add up to 180, and that's how many degrees there are in one triangle.