complementary angles

Two angles are called complimentary when their sum is equal to a right angle( $90^\circ$ ); and each is called the compliment of the other.

If $n_1, n_2\cdots n_i$ are complementary, then $n_1 + n_2 +\cdots +n_i = 90$ . How I remember this is: Co mplementary angles make a co rner.

If the sum of the measures of two angles is equal to $90$ degree, they are known as complementary angles to each other. Here, angle ADB and angle BDC is equal to $90$ degrees and complementary to each other.

COMPLEMENTARY ANGLES means $=\boxed{90°}$