Additional Links

 Adjacent Side     Hypotenuse     Length     Right Triangle     Sine     Tan     Tangent     Trigonometric Functions  

Cosine
Definition of Cosine

• In a right-angles triangle Cosine is the ratio of length of the adjacent side to the length of the hypotenuse.

More about Cosine

• Cosine is also written as cos.

Example of Cosine

• cos θ = & cos θ =

Solved Example on Cosine

If x = 8 units, y = 15 units, and a = 17 units, then find the value of cos C in the right triangle ABC.

Choices:
A.
B.
C.
D.
Correct Answer: D
Solution:
Step 1: Cos C =
Step 2: In ΔABC, the adjacent side of C is and the hypotenuse is .
Step 3: So, Cos C =
Step 4: = [Substitute BC = 8 and AC = 17.]

Related Terms for Cosine

• Adjacent Side
• Hypotenuse
• Length
• Right Triangle
• Sine
• Tan, Tangent
• Trigonometric Functions

Additional Links for Cosine

• Click here for samples
• Back to Mathematics Dictionary