how to find the perimeter of a 90 degree triangle?
['The perimeter of a shape is the length around the outside of that shape. ... ', 'A triangle has three sides, a, b, and c. ... ', 'P = a + b + c.', 'P = 3 + 4 + 5 P = 12.', "The Pythagorean Theorem is a formula that shows the relationship between the lengths of a right triangle's sides.", 'a^2 + b^2 = c^2.']