ACT Math : How to find a missing side with cosine

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #11 : Cosine

In a given right triangle , hypotenuse  and . Using the definition of , find the length of leg . Round all calculations to the nearest hundredth.

Possible Answers:

Correct answer:

Explanation:

In right triangles, SOHCAHTOA tells us that , and we know that  and hypotenuse . Therefore, a simple substitution and some algebra gives us our answer.

 Use a calculator or reference to approximate cosine.

 Isolate the variable term.

 

Thus, .

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