Lesson on Sine, Cosine, Tangent

Sin/Cos/Tan

​Right Triangle

Sine, Cosine, and Tangent are the main functions used in Trigonometry and are based on a right triangle.

Naming the Sides

It helps to give each side of the triangle a name:

​

"Opposite" is opposite the angle Θ​.

"Adjacent" is next to angle Θ​.

"Hypotenuse" is the long one.​

Multiple Choice

SPEED ROUND: If angle Θ is at point A, which side is b?

• Opposite

• Adjacent

• Hypotenuse

Multiple Choice

SPEED ROUND: If angle Θ is at point A, which side is a?

• Opposite

• Adjacent

• Hypotenuse

Multiple Choice

SPEED ROUND: If angle Θ is at point B, which side is a?

• Opposite

• Adjacent

• Hypotenuse

Multiple Choice

SPEED ROUND: If angle Θ is at point B, which side is c?

• Opposite

• Adjacent

• Hypotenuse

Multiple Choice

SPEED ROUND: If angle Θ is at point B, which side is b?

• Opposite

• Adjacent

• Hypotenuse

Sin/Cos/Tan

Sine, Cosine, and Tangent (often shortened to sin, cos, tan) are each a ratio of sides of a right triangle.

Sin/Cos/Tan

How can you remember this? Think "SOH CAH TOA"

Example #1

Solve for the missing sides

Example #1

Solve for the missing sides

Example #1

Solve for the missing sides

Multiple Choice

Solve for side y.

• 8.7

• 13

• 12

• 3.7

Multiple Choice

Solve for side x.

• 9.7

• 13

• 17

• 19

Multiple Choice

Solve for the side opposite angle Θ.

• 14

• 9.0

• 11

• 4.9

Multiple Choice

Solve for the side adjacent angle Θ.

• 13

• 6.0

• 11

• 4.9