**Understanding Various Types of Angles Junior High School Mathematics Lessons**

An angle is a shape formed by two rays or two straight lines whose bases coincide. This line is an infinite collection or collection of points. Angles are denoted using the symbol “∠”. Meanwhile, angle measurements are written in degrees (°). One of the tools for measuring angles is a protractor.

In general, protractors have two types of shapes, namely half circles (180°) and full circles (360°). Meanwhile, corners have three main components or parts, some of which are as follows:

- Corner legs (arms): the corner legs are the light lines that form the angle
- Corner point (vertex): this corner point is the starting point or can be called the intersection point where the light lines coincide or intersect
- Angle area: the corner area is the area between the two legs of the corner

**Understanding Various Angles**

**Zero degree angle (0°)**

In English this angle is called zero degree. A zero degree angle is an angle that has 0° where the two lines at the corner coincide with each other and do not form an angle area at all. This angle only looks like a straight line, even though it actually includes two lines that coincide with each other.

### Just imagine if two lines form some angle greater than zero degrees. So you can also imagine that one of the lines rotates towards the other line until they are both on the same line. The angle they created had shrunk from its original size to zero degrees. So the angle formed has a measure of zero degrees.

**Acute angle (0° < x < 90°)**

### An acute angle is a type of angle that has an angle ranging from 0° to less than 90°. The mathematical notation of this angle is 0° < x < 90°. Meanwhile, X is the size of the angle being measured, which is smaller than a right angle.

### In English, an acute angle is called an acute angle. A triangle formed by all angles that measure less than 90˚ is also known as an acute triangle. Polygons such as triangles, trapezoids, parallelograms, which consist of at least one acute angle in them.

**Right angle (90°)**

### A right angle is a type of angle that has a very precise angle measure of 90 degrees. This right angle results from two straight lines that intersect or meet each other, so that they can produce lines that are perpendicular to each other. The size of a right angle can be said to be greater than an acute angle and also smaller than an obtuse angle.

### In general, a right angle in English is known as a tight angle. If there is a triangle that has an angle of exactly 90 degrees, then the triangle is called a right triangle. Meanwhile, we can find right angles in everyday life, such as all the walls of the house, cupboards, clocks that show three o’clock, windows, photo frames, books and ceramics.

**Obtuse angle (90° < x < 180°)**

An obtuse angle is an angle that has an angle measuring more than 90 degrees or more precisely above 90 degrees and below 180 degrees. An obtuse angle can be said to be an angle whose angular magnitude is above a right angle and an acute angle. 90 degrees < x < 180 degrees (x is the angle measured).

Obtuse angles in English are generally known as obtuse angles. A triangle whose wrong angle has an angle greater than 90 degrees is called an obtuse triangle. Triangles that have obtuse angles are isosceles triangles and areosceles triangles.

Obtuse angles can be found in everyday life, such as boomerangs, clocks showing 7 o’clock, house roofs, rocking chairs, beach chairs, and hockey sticks.

**Straight angle (180°)**

An angle measuring 180 degrees is called a straight angle. It looks like a line. However, a straight angle is different from a 0 degree angle. Imagine two lines that form some angle greater than zero degrees. Then imagine one of the lines rotating in the opposite direction of the other line until they are both on the same line. This is what is called a straight angle.

### In English, a straight angle is called a straight angle. This straight angle looks like a straight line, but has two arms. On the other hand, a straight line has only one arm pointing in one direction.

**Reflex angle (180° < x < 360°)**

A reflex angle is an angle that has an angle ranging from 180° to less than 360°. Thanks to the angular magnitude of the reflex angle, the reflex angle can be said to be greater than obtuse angles, right angles and acute angles.

Above are several types of angles that you can understand for junior high school mathematics lessons. By reading the explanation above, it will certainly be very helpful for those of you who don’t understand the types of angles.

That’s a little information that we can discuss in this article. With the discussion above, hopefully this article can be helpful and useful.