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

1 Answer
May 16, 2018

The missing angle is 13^@13

Explanation:

Let angleBB be the missing angle.

Let angleAA be the angle that measures 77^@77

Let angle CC the right angle that measures 90^@90

The following is true of all triangles:

angleA+angleB+angleC = 180^@A+B+C=180

Express the above equation as angleBB in terms of the other angles:

angleB = 180^@-angleA-angleCB=180AC

Substitute the values for angle AA and angleCC

angleB = 180^@-77^@-90^@B=1807790

angleB = 13^@B=13