algebra
posted by Terri .
Television sets: What does it mean to refer to a 20inch TV set or a 25inch TV set. Such units refer to the diagonal of the screen. A 25inch TV set also has a width of 20inches. What is its height? Height of a 25inch TV. _______inches

Use the Pythagorean Theorem.
a^2 + b^2 = c^2
a^2 + 20^2 = 25^2
a^2 + 400 = 625
a^2 = 225
a = 15