Right Angle – Definition with Examples

In geometry, when two rays meet each other at a common point, they form an angle. The point of meeting of the two rays is known as the vertex.

Angles are measured in degrees (symbol: °) 

Angle measuring 62 degrees

Some common types of angles are acute angles, right angles, and obtuse angles.

Types of angles are acute angles, right angles, and obtuse angles.

Right angle 

When two straight lines intersect each other at 90˚ or are perpendicular to each other at the intersection, they form the right angle. A right angle is represented by the symbol ∟.

Right Angle

The given image shows various formations of the right angle.

Various formations of the right angle

We can find the right angles in shapes.

A square or rectangle has four corners with right angles.

Rectangle has four corners with right angles

Examples of right angles are all around us. We can see right angles in the corners of a room, book, cube, windows and at several other places.

A vertical and a horizontal line makes the most common right angles. However, diagonal lines intersecting each other also form right angles. If you draw the diagonals of a square, a rhombus or a kite, the angle at the intersection is 90 degrees and is, therefore, a right angle.

Angle at the intersection is 90 degrees.

How to Draw a Right Angle Using A Protractor?

  1. Start by drawing a horizontal line.
Step 1 to draw a right angle using protractor
  1. Now place the protractor on the horizontal line.
Step 2 to draw a right angle using protractor : Protractor on the horizontal line
  1. Measure 90˚ and mark it with a point.
Step 3 to draw a right angle using protractor :  Measure 90˚
  1. Now using a scale, draw a straight line from this point to the horizontal line.
Step 4 to draw a right angle using protractor : draw a straight line from this point to the horizontal line

Fun Facts 

  1. All right angles are the same.
  2. All right angles correspond to a quarter of a complete turn.
  3. All triangles with one angle right are called right-angled triangles.

Solved Examples

  1. Find the number of right angles in the figure shown below. 
Solved Example of right angle

Solution: The above figure is a rectangle. The number of right angles in the above figure is 4. Each side in the figure meets the adjacent side at 90°. 

  1. If the two lines PQ and RS are perpendicular, what is the measure of ∠SOT?
Measure of ∠SOT? when pq and rs are perpendicular

Solution:

              Since, line PQ ⟂ line RS, m∠SOQ=90°

Moreover, m∠SOQ=m∠QOT+m∠SOT

90°=30°+m∠SOT

Therefore, m∠SOT=90°-30°=60°

  1. How many right angles are there in the given figure?
Count the right angles

Solution:

The given figure shows 3 right angles and 2 obtuse angles.

Practice Problems

Right Angle

Attend this Quiz & Test your knowledge.

1How many right angles are there in a square?

4
2
3
1
CorrectIncorrect
Correct answer is: 4
Explanation: A square contains 4 angles, and all of them measure 90°.

2How many right angles are present in the given figure?

Right Angle – Definition with Examples
2
4
3
0
CorrectIncorrect
Correct answer is: 2
Explanation: The given figure shows a quadrilateral with two right angles.

3A right-angled triangle has one angle measuring 90°. What is the sum of the measures of the other two angles?

$\lt$ 90°
$\gt$ 90°
= 90°
$\gt$ 180°
CorrectIncorrect
Correct answer is: = 90°
Explanation: The three interior angles of any triangle add up to 180°. Since one of the interior angle in a right-angled triangle is 90°, the other two interior angles must add up to 90°.

4How many right angles are required to make a 180° angle?

3
6
5
2
CorrectIncorrect
Correct answer is: 2
Explanation: Two right angles would together form a 180° angle.

Frequently Asked Questions

A triangle can only have one right angle as it consists of only three angles. A triangle can’t have more than one right angle. 

T, L, H, and E are some alphabets of the English language that show right angles. 

Squares, rectangles and right triangles all have right angles.  

A total of four right angles are required to make a 360° angle. A 360-degree angle is a full circle.