Acute Angles

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Acute Angles in Detail

Angles are usually measured in degrees. An acute angle is a kind of an angle that measures between 0° and 90°, which means it is smaller than a right angle (L shape). An acute angle has a horizontal “V” shape. Acute angles are an elementary concept of geometry that have wide applications. There are three fundamental types of angles, and they are acute angle, right angle, and obtuse angle.


How to Remember Acute Angles?

Sometimes we get confused between the acute angles meaning and obtuse angles meaning. To remember the meaning of acute angle and identify it in an easy way, you can remember that the smallest angle in a triangle is an acute angle. We already know that the measure of an acute angle is less than 90°. Therefore, acute angle examples are 25°, 36°, 47°, 80°, and so on. Students can follow the formula of an acute angle to solve the sums of geometry.


Measurement of Acute Angles

An acute angle comprises two rays or line segments. The two-line segments meet at one endpoint of an acute angle. One line segment forms the base of the angle, while the line segment forms the arm of the angle. An acute angle can be measured by reading the angle measures on the protractor anti-clockwise. The acute angle can be constructed and measured with the help of a protractor. Acute angles are considered to be sharp angles. To have a precise idea about an acute angle degree diagrammatically, students can follow the image shown below.


Acute Angle

∠ABC measures 30° and hence it is an acute angle.

FAQ (Frequently Asked Questions)

1. What are the Five Types of Angles?

Ans. The five types of angles are acute angle (< 90°), obtuse angle (> 90°), right angle (= 90°), straight angle (= 180°), reflex angle (> 180°). There is another angle which measures 360° and is called full rotation of the axis.

2. Can a Triangle Have Only One Acute Angle?

Ans: No, a triangle cannot have only one acute angle. If a triangle has 1 obtuse angle, the other two angles will have to be either right angles or obtuse angles. It is not possible as the summations of interior angles of a triangle are always 180°. So, every triangle requires at least 2 acute angles.

3. How Can You Measure Angles?

Ans: Angles can be measured by using a protractor. First, we need to place the center of the protractor at a fixed point. We can consider one arm of an angle as the base. When we measure from the base of the angle in an anti-clockwise manner till the other arm, we will get the degree of the angle.