9514 1404 393
Answer:
Triangle Angle Sum
Explanation:
Corresponding angles applies to parallel lines crossed by a transversal, or to angles in similar figure. The term has no meaning in this geometry.
Supplementary angles refers to a pair of angles that have a sum of 180°. Usually these are seen in quadrilaterals and figures involving parallel lines. The term has no meaning in this geometry.
The Pythagorean theorem relates side lengths in a right triangle. It has no utility in this geometry. Here we're concerned with angles, not sides.
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The theorem useful for finding x is the Triangle Angle Sum theorem, which tells you the sum of angles in a triangle is 180°. That theorem lets you write a linear equation involving x, so that x can be found.
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(3x -2) +(x +8) +(2x +3) = 180
6x +9 = 180
x = 171/6 = 28.5°
The three angles are 36.5°, 60°, 83.5°.