Acute Angle: Definition and Examples

Acute Angle

Definition

The Acute Angle is an angle whose measurement is greater than 0° and less than 90°.

Note this definition in the figure below:

The acute angle is a very common angle, we see it in different geometric figures such as: triangle, rhombus, circumference, and so on.

Examples:

Note different examples of acute angles.

In this figure, note how angles depending on their size have different «openings»; in addition, they could also be considered as examples of acute angles: 1°, 15°, 89.9999° and all those angles that are within: 0° < α < 90°

Measurement of an Acute Angle

Measuring an acute angle is a simple task, for which a protractor must be used. Then, the 90° angle is located and the angles below it will be acute angles, except for the 0° angle, by definition.

See how it is done:

Here an acute angle equal to 60° has been measured, which is the characteristic angle of an equilateral triangle.

¡Important!

Another geometric figure where we see two acute angles is in the isosceles triangle, see the following graph:

The angles «α» are acute; but, «θ» can be acute, right or obtuse.