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?
- Start by drawing a horizontal line.
- Now place the protractor on the horizontal line.
- Measure 90˚ and mark it with a point.
- Now using a scale, draw a straight line from this point to the horizontal line.
Fun Facts
- All right angles are the same.
- All right angles correspond to a quarter of a complete turn.
- All triangles with one angle right are called right-angled triangles.
Solved Examples
- 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°.
- 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°
- How many right angles are there in the given figure?
Solution:
The given figure shows 3 right angles and 2 obtuse angles.
Practice Problems
Right Angle
1How many right angles are there in a square?
Explanation: A square contains 4 angles, and all of them measure 90°.
2How many right angles are present in the given figure?
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?
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?
Explanation: Two right angles would together form a 180° angle.
Frequently Asked Questions
How many right angles are present in a triangle?
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.
What alphabets of the English language show right angles?
T, L, H, and E are some alphabets of the English language that show right angles.
What shapes have right angles?
Squares, rectangles and right triangles all have right angles.
How many right angles are required to make a 360° angle?
A total of four right angles are required to make a 360° angle. A 360-degree angle is a full circle.