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Use the Triangle Angle Sum Theorem. Then consider Theorem 5.10 about Angle-Side Relationships in Triangles.
Angles: ∠ X, ∠ Y, ∠ Z
Sides: YZ, XZ, XY
On the diagram, we are given the expressions for the interior angles of △ XYZ.
| m∠ X = (2x+1)^(∘) | m∠ Y = (2x+9)^(∘) | |
|---|---|---|
| Substitution | (2( 20)+1)^(∘) | (2( 20)+9)^(∘) |
| Calculation | 41 ^(∘) | 49 ^(∘) |
Comparing the angle measures, we can see that the smallest angle is ∠ X, followed by ∠ Y and then ∠ Z.
m∠ X < m∠ Y
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Angle-Side Relationships in Triangles |
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If one angle of a triangle has a greater measure than another angle, then the side opposite the greater angle is longer than the side opposite the lesser angle. |
Now, by this theorem, we will look for the corresponding opposite sides. cc Angle & Opposite Side [0.5em] ∠ X & YZ [0.5em] ∠ Y & XZ [0.5em] ∠ Z & XY From here, we can list the sides in order from smallest to largest. YZ < XZ < XY