7.4.1 SPECIAL RIGHT TRIANGLES

Chapter 7: Right Triangles and Trigonometry

45⁰ - 45⁰ - 90⁰ Triangle (Isosceles)

Remember our warm up, half a square:If you know the side length, the hypotenuse is

that number times 2If you know the hypotenuse, divide by 2

x 2

x

x

45⁰

45⁰

90⁰

2

2

2

xx

x

2

2x

Solve for x

766

x

45⁰ x

2

2

x

342

342

12x

45⁰

30⁰ – 60⁰ - 90⁰ Triangle

Equally as important, the 30⁰ – 60⁰ - 90⁰ Triangle has these given ratios.

The best way to solve this is to find the length of the shorter side (across from the 30⁰)

60⁰

30⁰

x2x

3xShort Side

Long SideHypotenuse

Mul

tiply

by

3

Double

Half

D

ivid

e by

3

2

3bymultiply

3

2bymultiply

Solve for x and y

60⁰

30⁰

17y

x 60⁰

30⁰ x

3

y60⁰

30⁰

x

y

6

Homework

p.461 1, 3 – 5, 7 – 18, 23 - 28