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mezya [45]
4 years ago
12

Find cos B exactly if a = 15, b = 11, and angle Cis a right angle

Mathematics
1 answer:
astra-53 [7]4 years ago
3 0

Answer:

Final answer is \cos\left(B\right)=\frac{15}{\sqrt{346}} which is the last choice.

Step-by-step explanation:

In triangle ABC, we have been given a = 15, b = 11, and angle C is a right angle.

Now using those values, we need to find the exact value of cos B.

Apply Pythagorean formula:

AB^2=AC^2+BC^2

AB^2=11^2+15^2

AB^2=121+225

AB^2=346

AB=\sqrt{346}

Now apply formula of cos

\cos\left(B\right)=\frac{BC}{AB}

\cos\left(B\right)=\frac{15}{\sqrt{346}}

Hence final answer is \cos\left(B\right)=\frac{15}{\sqrt{346}}


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