6.3-6.4 Trig Ratios - Finding Sides and Angles

Front

What is the definition of a right triangle?

Back

A right triangle is a triangle that has one angle measuring 90 degrees.

Front

What are the three sides of a right triangle called?

Back

The three sides are called the hypotenuse (the longest side), the opposite side (the side opposite the angle of interest), and the adjacent side (the side next to the angle of interest).

Front

What does SOH-CAH-TOA stand for?

Back

SOH-CAH-TOA is a mnemonic for remembering the definitions of the sine, cosine, and tangent functions: SOH = Sine = Opposite/Hypotenuse, CAH = Cosine = Adjacent/Hypotenuse, TOA = Tangent = Opposite/Adjacent.

Front

If you know the hypotenuse and the opposite side, which trig function do you use to find the angle?

Back

You use the sine function.

Front

What is the formula for finding the cosine of an angle in a right triangle?

Back

Cosine of an angle = Adjacent side / Hypotenuse.

Front

How do you find the length of the opposite side if you know the angle and the hypotenuse?

Back

Use the formula: Opposite side = Hypotenuse * sine(angle).

Front

What is the formula for finding the tangent of an angle in a right triangle?

Back

Tangent of an angle = Opposite side / Adjacent side.

Front

If the adjacent side is 5 cm and the hypotenuse is 13 cm, what is the cosine of the angle?

Back

Cosine = Adjacent / Hypotenuse = 5/13.

Front

What is the relationship between the angles in a right triangle?

Back

The sum of the two non-right angles in a right triangle is always 90 degrees.

Front

How do you find the measure of an angle using the tangent function?

Back

Use the formula: angle = arctan(Opposite / Adjacent).