# 45 45 90 right triangles Some right triangles

• Slides: 8

45 -45 -90 right triangles Some right triangles are used so frequently that it is helpful to remember some of their properties. These triangles are called special right triangles The 2 most common are the 45 -45 -90 triangle and the 30 -60 -90 triangle. Since the 45 -45 -90 triangle has 2 angles with equal measures, it is also an isosceles right triangle

Properties of a 45 -45 -90 triangle: side lengths § In a 45 -45 -90 right triangle, both legs are congruent and the length of the hypotenuse is the length of the leg multiplied by

Finding side lengths in a 45 -45 -90 triangle § Use the properties to find the length of the hypotenuse of the triangle 45 2 in § The length of the hypotenuse is equal to the length of the leg times

Finding side lengths § Find the length of a leg of the triangle 3 ft 45 § The length of the hypotenuse is the length of the leg times

Finding perimeter of a 45 -45 -90 triangle § Find the perimeter 12 yd. 45 § 12 + ? = Perimeter

§Though it is faster to use the properties of 45 -4590 triangles to find unknown lengths, the Pythagorean theorem can still be used

Applying Pythagorean theorem § Find the length of the missing sides using Pythagorean theorem 45 125 ft

review § 1. Find the length of the hypotenuse in a 45 -45 -90 triangle with a leg of 31 yd. § 2. Find the length of a leg in a 45 -45 -90 triangle if the hypotenuse is 63 m. § 3. Find the perimeter of a right triangle with an 45 degree angle and a leg of 18 in. § 4. A square building has a diagonal of 150 feet. What would be the square footage of 1 floor of the building.