### Home > MC2 > Chapter 5 > Lesson 5.3.1 > Problem5-90

5-90.

Decide if these angles are acute, obtuse, or right angles. All diagrams are drawn to scale.

Acute angle: An angle with a measure between (but not including) $0°$ and $90°$.
Right angle: An angle measuring $90°$.
Obtuse angle: An angle with a measure between (but not including) $90°$ an $180°$.

To determine the type of angle, use a $90°$ angle as a reference point.

1. Since the angle is greater than $90°$, it is obtuse.

1. Acute angle