Answer: The missing angle is 13°
Step-by-step explanation:
Let ∠B
be the missing angle.
Let ∠A
be the angle that measures
77∘Let ∠C
the right angle that measures
90∘
The following is true of all triangles:
∠A+∠B+∠C=180∘
Express the above equation as
∠B
in terms of the other angles:
∠B=180∘−∠A−∠C
Substitute the values for ∠A and ∠C
∠B=180∘−77∘−90∘
∠B=13∘
