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Geometry

Angles and Lines

Intro

Concept Quizzes

Geometry Warmup - Angles and Lines
Basic Angle Chasing
Types of Angles
Complementary and Supplementary Angles
Parallel Lines
Perpendicular Lines
Patterns In Geometry
Angles and Lines - Problem Solving

Challenge Quizzes

Angles and Lines: Level 1 Challenges
Angles and Lines: Level 2 Challenges
Angles and Lines: Level 3 Challenges

Types of Angles

How many acute angles does an obtuse triangle have?

0 1 2 3

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by Brilliant Staff

In the above diagram, $A,$ $B,$ and $C$ lie on a straight line. If $\color{#3D99F6}{ \angle ACD ={151}^\circ},$ which of the following is true of $\color{#D61F06} { \angle BCD}$ ?

It is an obtuse angle. It is an acute angle. It is a right angle. It is a straight angle.

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by Brilliant Staff

Angles $ABC$ and $CBD$ are adjacent with common vertex $B$ and common edge $\overline{BC}.$ If $\angle ABC={51}^\circ$ and $\angle CBD={40}^\circ,$ which of the following is true of $\angle ABD?$

It is acute. It is a right angle. It is obtuse. Cannot be determined.

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by Brilliant Staff

If $\angle A$ is an acute angle, $\angle B$ is a right angle and $\angle C$ is an obtuse angle, which of the following is true of $\angle A+\angle B+\angle C ?$