Angles, Lines, and Polygons
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- Finding an angle measure of a triangle given two angles
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- Identifying parallel and perpendicular lines
- Naming segments, rays, and lines
- Acute, obtuse, and right angles
- Measuring an angle with the protractor
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Finding an angle measure of a triangle given two angles
Finding an angle measure of a triangle given two angles
The sum of angles of a triangle is 180°.
In a triangle, we know there are three angles and three sides. In this lesson we solve for missing angle measure given two angle measures in a triangle.
Find the missing angle in the given triangle below. Sum of angles in a triangle is 180°.
Solution
Step 1:
Sum of angles in a triangle is 180°.
29° + 33° + b = 180°; 62° + b = 180°
Step 2:
b = 180° − 62° = 118°
So missing angle = 118°
Find the missing angle in the given triangle below. Sum of angles in a triangle is 180°.
Solution
Step 1:
Sum of angles in a triangle is 180°.
29° + 33° + b = 180°; 62° + b = 180°
Step 2:
b = 180° − 62° = 118°
So missing angle = 118°