A right angle is an angle that measures 90 degrees. It is the most commonly seen angle in our day-to-day life. It can be seen in the corners of a room, the edges of boxes, the screen of a mobile phone, and so on. The sides of a square and a rectangle always form a right angle with each other. In radians, it is represented as π/2. Let us discuss more about a right angle in this article.
|1.||What is a Right Angle?|
|2.||Right Angle Shapes|
|3.||Right Angle Calculator|
|4.||Triangle with Right Angle|
|5.||FAQs on Right Angle|
What is a Right Angle?
A right angle is an angle of 90°. When two rays intersect and form a 90˚ angle or are perpendicular to each other at the intersection, they are said to form a right angle.
Right Angle Definition
The angle formed by two lines that are perpendicular to each other is called a right angle. A right angle is equal to 90° and is in the shape of the letter "L". In the following figure, ray AB and BC form a right angle ABC.
Right Angle Shapes
A right angle looks like the alphabet L. It can be observed in many shapes, like the angle made by the clock hands at 3:00 p.m. We can also see them in the places like:
- Edges of a door.
- Four edges of a television.
- Corner of the chair.
- Mobile screen.
Try to identify and notice the right angles in the following shapes.
Right Angle Calculator
Some of the devices used for measuring a right angle are protractors, try squares, and set squares. Right angle calculators are used to check if the given angle is a right angle or not. We align the sides of set squares with the given angle and check if the angle is matching with the sides of the set squares. Similarly, we use a try square to check if the given angle is the exact match of the shape of the sides of the try square. The baseline of the protractor should match with the base of the given unknown angle, and then we check if the other ray of the angle passes exactly from the 90-degree mark on the protractor or not. If the ray passes through the 90-degree mark, then it is a right angle otherwise not.
The most commonly used right angle calculators are shown below:
Triangle with Right Angle
There is one more place where the right angle is used and that is a right-angled triangle. If among the three angles of a triangle, one angle is 90°, then that triangle is called a right-angled triangle. Since the three interior angles of a right-angled triangle add to 180°, and if one angle is always 90°, then the other two angles must always add to 90°.
Tips and Tricks on Right Angle:
Here is a list of a few points that should be remembered while studying about right angle:
- Right angles can easily be measured by protractors, set squares, and try squares.
- The most common examples of right angles are the edges of a door, the four edges of a television, 9:30 of the analog clock, and the corner of a notebook.
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Right Angle Examples
Example 1: Trevor wants to know which types of angles are greater than the right angle. Can you help him figure out this problem?
From the right angle definition, any angle whose measure is greater than 90° is greater than a right angle. They are:
(a) Obtuse angle - that lies between 90° and 180°
(b) Straight angle - exactly 180°
(c) Reflex angle - lies between 180° and 360°
(d) Complete angle - exactly 360°.
Example 2: Fiona saw the clock in her home and she was curious to know the angle made by the two hands of a clock at 3:00 p.m and 9:00 p.m. Find the angle made by the clock hands at 3:00 p.m and 9:00 p.m.
We can see in the picture that the two hands of the clock form an L-shaped angle that is a right angle.
Answer: The angle formed by the clocks at 3:00 p.m and 9:00 p.m is a right angle.
Example 3: If the sum of two angles ∠1 and ∠2 is a right angle and ∠2 measures 30°, what will be the measurement of ∠1?
It is given that ∠2 = 30°, and ∠1 + ∠2 = 90°. By substituting the value of ∠2 in the equation, we get, ∠1 + 30° = 90°.
⇒ ∠1 = 90° - 30°
⇒ ∠1 = 60°
Therefore, the value of ∠1 is 60°.
FAQs on Right Angle
What is a Right Angle?
A right angle is an angle with a value equal to 90°. When two rays intersect and form a 90˚ angle at the intersection, they are said to form a right angle. It is the most commonly seen angle in our day-to-day life. We can see it in many places like the corners of a window, the edges of a cupboard, the screen of a mobile phone, and so on.
How Many Degrees Does a Right Angle have?
A right angle is a 90-degree angle. It is formed when two lines intersect each other at a 90-degree angle.
What Angle is a Right Angle?
When two rays meet at 90°, they form a right angle. In radians, it is represented as π/2.
How to Identify a Right Angle?
A right angle can be easily identified with the letter L. It is the angle between the leg and arm of the letter L. If the letter L can be formed anywhere on the given shape, it can be termed as a right angle.
Is a Right Angle Only 90 Degrees?
Yes, a right angle is always equal to 90°. It can never be other than this angle and can be represented as π/2 in radians. Any angle less than 90° is an acute angle and the angle which is greater than 90° but less than 180° is an obtuse angle.
How to Measure a Right Angle?
We can use protractors, set-squares, or try squares to measure a right angle. We just need to place them properly and check the measurement and position.
What is a Right Angled Triangle?
A right-angled triangle is a triangle in which one angle is 90°. Since a 90-degree angle is called a right angle, the triangle with a right angle is called a right triangle or a right-angled triangle.