SOHCAHTOA

SOHCAHTOA is an acronym for trig functions and right triangles and stuff.

Sin(theta) = Opposite/Hypotenuse

Cos(theta) = Adjacent/Hypotenuse

Tan(theta) = Opposite/Adjacent

Here's some rules:

1.) You can only use it on right triangles.

2.) No using it on the 90 degree angle.

3.) Angle of elevation = looking from bottom to top

4.) Angle of depression = looking from top to bottom

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SOCHAHTOA in action(these problems are all word problems)

The safety instructions for a 20 foot ladder indicate that the ladder should not be inclined at more than 70 degrees from the ground. Suppose a ladder is leaned against a house at this angle. Find the distance from the base of the house to the foot of the ladder(x) and the height of the ladder(y).

Find the height of the ladder first.

sin70 = y/20 so y = 20sin70

y = 18.79

Next find the length along the ground(from the house to the ladder).

cos70 = x/20 so x = 20cos70

x = 6.84

Voila.