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Complementary Angles
What are Complementary Angles?
Complementary Angles
in geometry have the following characteristics. When two angles add up to 90° degrees they are called Complementary Angles. For an example, closely look at the picture below. We have a
Right Angles
∠DBC
which is a 90° angle. This 90° angle is cut in two by
ray
BE
. So now the 90° is divided in to two smaller angles that add up to 90°. Now let us express this definition in geometric math terms.
Another way to say angles are complementary is if two angles next to one another are
Right Angles
.
Complementary angles have length but no width or height.
If we look at the diagram below, the two adjacent angles are
∠DBE
and
∠EBC
. The sum of these two angles are 90° because they form a right angle.
Let us assume that angle
∠DBE
is 65°. That means that 65° plus
∠EBC
equals 90°. Taken to the next step, 90° - 65° =
∠EBC
= 25°.
See More About Angles