Special Right Triangles

45-45-90 Right Triangle

An isosceles triangle that is half of a square

45-45-90: The legs are always ___________________________

Congruent

45-45-90: If you know a leg, do this to find the hypotenuse:

multiply by √2

30-60-90: always find the ________________ leg first

small (across from 30 degrees)

45-45-90: If you know the hypotenuse, do this to find the legs:

divide by √2

30-60-90 Right Triangle

Type of triangle formed when an altitude is drawn in an equilateral triangle

30-60-90: To find the medium leg do this to the small leg:

multiply by √3

30-60-90: To find the small leg do this to the medium leg:

divide by √3

30-60-90: To find the hypotenuse do this to the small leg:

multiply by 2

30-60-90: To find the small leg do this to the hypotenuse:

divide by 2

Pythagorean Theorem

c²=a²+b²

If c²=a²+b², then the triangle is a/an _______________________ triangle.

Right

If c²>a²+b², then the triangle is a/an _______________________ triangle.

Obtuse

If c²<a²+b², then the triangle is a/an _______________________ triangle.

Acute