1. 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 triangle and the triangle.
Since the triangle has 2 angles with equal measures, it is also an isosceles right triangle

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

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

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

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

6. Though it is faster to use the properties of triangles to find unknown lengths, the Pythagorean theorem can still be used

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

8. review
1. Find the length of the hypotenuse in a triangle with a leg of 31 yd.
2.Find the length of a leg in a triangle if the hypotenuse is 63 m.
3. Find the perimeter of a right triangle with an45 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.