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In ΔQRS, s = 4.2 cm, m∠R=160° and m∠S=8°. Find the length of r, to the nearest 10th of a centimeter.

1 Answer

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Answer:

10.3 cm

Explanation:

You want the measure of side 'r' in triangle QRS, given s = 4.2 cm, R = 160°, and S = 8°.

Law of sines

The law of sines tells you side lengths are proportional to the sine of the opposite angle.

r/sin(R) = s/sin(S)

r = s×sin(R)/sin(S) = (4.2 cm)sin(160°)/sin(8°)

r ≈ 10.3 cm

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