In triangle ABC, m∠ a=45∘, m∠b65∘, and c=20. Find b. Round your answer to the nearest tenth.

Question

Mathematics

Hailee Villarreal

12 March, 03:07

In triangle ABC, m∠ a=45∘, m∠b65∘, and c=20. Find b. Round your answer to the nearest tenth.

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Answers (1)

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Aryana Burns · Answer 1

First we find the missing angle which is "C".

We already know they add up to 180º, so that means you add the two given angles that is 45+65 which gives you 110º and then subtract 180-110=70º, C=70º and now you have all three angles and just need to find the side.

To find that side, you'll have to use Sines.

Sin (70) / 20 = Sin (65) / b

cross multiply and you have something like 20 * Sin (65) / Sin (70) = b * Sin (70) / Sin (70)

b = 11.7