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2. Find the measure of angle j.

2. Find the measure of angle j.-example-1

1 Answer

1 vote

Answer:

(a) 54.1°

Explanation:

The Law of Cosines can be used to find the angle measure when three sides lengths are given.

j² = k² +l² -2kl·cos(J)

J = arccos((k² +l² -j²)/(2kl)) = arccos(789/1344) ≈ 54.0518°

The measure of angle J is about 54.1°.

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Additional comments

A triangle solver makes short work of a question like this. Triangle solver apps are available for phone or tablet, and are available on the web (as used here). Your calculator may have one built in.

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As a rough approximation of the angle measures, you can assume they are nearly proportional to the side lengths. Then angle J would be ...

J/180° = j/(j+k+l) = 26/(26+32+21) = 26/79

J ≈ 180°×26/79 ≈ 59.2°

This is sufficient to tell you the angle is not 40° and not 85°.

2. Find the measure of angle j.-example-1
User Benno Kress
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