Question

A right triangle has one angle that measures 77°. What is the measurement for the missing angle?

Answer 1

The missing angle is `13^@`

Explanation:

Let `angleB` be the missing angle.

Let `angleA` be the angle that measures `77^@`

Let `angle C` the right angle that measures `90^@`

The following is true of all triangles:

`angleA+angleB+angleC = 180^@`

Express the above equation as `angleB` in terms of the other angles:

`angleB = 180^@-angleA-angleC`

Substitute the values for `angle A` and `angleC`

`angleB = 180^@-77^@-90^@`

`angleB = 13^@`