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In triangle ABC, which side is the longest if these are the measures of the angles?

measure angle A = 60 degrees, measure B = 3x-2 degrees, measure C = 2x + 7 degrees

Side ____ is the longest side.

1 answer

To determine which side of triangle ABC is the longest, we need to find the actual measures of angles B and C first.

We know that the sum of the angles in a triangle is 180 degrees:

\[
\text{Measure angle A} + \text{Measure angle B} + \text{Measure angle C} = 180^\circ
\]

Given:
\[
\text{Measure angle A} = 60^\circ
\]
\[
\text{Measure angle B} = 3x - 2
\]
\[
\text{Measure angle C} = 2x + 7
\]

Using the angle sum property of the triangle:

\[
60 + (3x - 2) + (2x + 7) = 180
\]

Combine like terms:

\[
60 - 2 + 7 + 3x + 2x = 180
\]

\[
65 + 5x = 180
\]

Isolating \( x \):

\[
5x = 180 - 65
\]

\[
5x = 115
\]

\[
x = 23
\]

Now, substitute \( x = 23 \) back into the expressions for angles B and C:

\[
\text{Measure angle B} = 3x - 2 = 3(23) - 2 = 69 - 2 = 67^\circ
\]

\[
\text{Measure angle C} = 2x + 7 = 2(23) + 7 = 46 + 7 = 53^\circ
\]

Now we know the measures of the angles:
\[
\text{Measure angle A} = 60^\circ
\]
\[
\text{Measure angle B} = 67^\circ
\]
\[
\text{Measure angle C} = 53^\circ
\]

In a triangle, the longest side is opposite the largest angle. Here, the largest angle is \( \text{Measure angle B} = 67^\circ \).

Therefore, the side opposite angle B, which is side AC, is the longest side.

Side **AC** is the longest side.