Supplementary Angles – Definition & Examples

Do you know we are all surrounded by angles? Some real-life examples of supplementary angles are cups, logos, and stars. Have you ever thought that supplementary angles and complementary angles have derived from the word Complement and Supplement. When two angles add up to 180 degrees are said to be supplementary angles. When two angles are supplementary, if

• One of the angles is an acute angle and another angle is an obtuse angle.
• When both of the angles are right angles.

Complementary Angles – Definition

Complementary angles are those angles when two angles sum up to measure 90 degrees, they are called Complementary Angles. Since they are composed of two acute angles measuring less than 90 degrees. Complementary angles are put together when they form a right angle that sums up to 90 degrees. If you want to learn more about these angles in detail and in an interesting way, visit Cuemath.

Examples of Supplementary Angles in Real Life

• You pass by a road every day but have you seen some roads meeting up and making a supplementary angle. Try to find out if you haven’t.
• You all must have eaten a cake but have you ever noticed a cake which is in a square shape as you know all the angles of the square are 90 degrees and they make a supplementary angle because their sum is 180 degrees.

Properties of Supplementary Angles

The important properties of supplementary angles are:-

• When two angles are said to be supplementary angles when they add up to 180°.
• When two angles together make a straight line, but the angles need not be together.
• “S” of supplementary angles denotes the “Straight” line. This means they form 180°.
• Supplementary angles are important because it helps to find other angles.

Difference Between Supplementary and Complementary Angles

Have you ever learned the difference between supplementary and complementary angles in such an easy way? If not, then here it is for you.

Supplementary Angles	Complementary Angles
Sum of 90 degrees	Sum of 180 degrees
Form a right angle	It lies on the same side of a straight line

Real-Life Examples of Complementary Angles

• Have you ever noticed that if a rectangular piece of bread is cut into two pieces along the diagonal, we get two right triangle shapes from them, with a pair of complementary angles. As you all eat bread every day but must have not found that it might give you a live example of a complementary angle.
• A wall clock, where the minute hand is at 12 and the hour hand is at 3, gives a complementary angle. Have you ever noticed this? If not, then find out.
• Crossroads are also an example of complementary angles.
• Have you ever seen a magnetic compass that is used for navigation? We can see the North and the East direction on the compass and in the middle, it is the pointer of the compass. When the angle is formed between the North direction and the compass pointer represents the complementary angle similarly the pointer and the East direction on the compass will also form the complementary angle.
• Even the flap of an envelope always forms a right angle when held vertically from its horizontal base. When the flap is moved up or down, it forms two angles that are always complementary. You must have never noticed this though you must be using an envelope to write some greetings on top of it.

So, by now you must be wondering about all these angles which you could have noticed around you but you never observed these things. As we always say, keep your eyes open and observe things around you.