Question

Find a. Round to the nearest tenth.

Answer 1

9514 1404 393

Answer:

  21.8 cm

Step-by-step explanation:

A useful way to write the Law of Sines relation when solving for side lengths is ...

  a/sin(A) = b/sin(B)

Then the solution for 'a' is found by multiplying by sin(A):

  a = sin(A)(b/sin(B)) = b·sin(A)/sin(B)

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We need to know the angle A. Its value is ...

  A = 180° -75° -31.8° = 73.2°

Then the desired length is ...

  a = (22 cm)sin(73.2°)/sin(75°) ≈ (22 cm)(0.9573/0.9659)

  a ≈ 21.8 cm

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I like to use the longest side and largest angle in the equation when those are available. That is why I chose 75° and 22 cm.