# 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: °)

Some common 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 ∟.

The given image shows various formations of the right angle.

We can find the right angles in shapes.

A square or 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.

## How to Draw a Right Angle Using A Protractor?

1. Start by drawing a horizontal line.
1. Now place the protractor on the horizontal line.
1. Measure 90˚ and mark it with a point.
1. Now using a scale, 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.

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?

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?

Solution:

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

## Practice Problems

### 1How many right angles are there in a square?

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

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

2
4
3
0
CorrectIncorrect
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
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°.

3
6
5
2
CorrectIncorrect