Answer:
- 39°
- x = 38
Step-by-step explanation:
You want the measure of the third angle in a triangle in which two of the angles are 108° and 33°. You also want the measure of x where consecutive exterior angles at a transversal are (2x -15) and (3x +5).
1. Angle
The sum of angles in a triangle is 180°, so the measure of the third can be found by subtracting the other two from 180°:
x = 180° -108° -33° = 39°
The missing angle measure is 39°.
2. Variable
The two marked angles are "consecutive exterior angles" so have a sum of 180°. This can be used to write an equation.
(2x -15) +(3x +5) = 180
5x -10 = 180 . . . . . . . . . . . simplify
x -2 = 36 . . . . . . . . . . . divide by 5
x = 38 . . . . . . . . . . . add 2
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Additional comment
The two angles are 2(38)-15 = 61°, and 3(38)+5 = 119°. They total 180°.
There are a number of relationships involving angles in various geometries. It is helpful to remember them, or at least keep a handy list.