Understanding Angle Sum Theorem
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Beginner
Start here! Easy to understand
Beginner Explanation
In any triangle, if you add up the measures of the three interior angles, you will always get $180^\circ$.
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Practice Problems
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1
Quick Quiz
Single Choice Quiz
Beginner
If the measures of two angles in a triangle are $65^\circ$ and $55^\circ$, what is the measure of the third angle?
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2
Real-World Problem
Question Exercise
Intermediate
Teenager Scenario
In a game of pool, you strike the white cue ball so that it first bounces off a cushion and then contacts two other balls. Draw lines from the point of cushion contact to each target ball; these lines form a $120^\circ$ angle. What angle of incidence (the angle between the incoming path and the cushion) ensures the angle of incidence equals the angle of reflection?
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3
Thinking Challenge
Thinking Exercise
Intermediate
Think About This
If the exterior angle of a triangle is $110^\circ$, and one of the interior opposite angles is $40^\circ$, what is the measure of the other interior opposite angle?
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4
Challenge Quiz
Single Choice Quiz
Advanced
A triangle has interior angles in the ratio 1:2:3. What is the measure of the smallest angle?
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Recap
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