Question

What is the measure of the missing angle in the figure below?

Answer 1

Sum of all interior angles in a triangle = 180
let missing angle = x

x + 144 + 13 = 180
x + 157 = 180
x = 23

answer
23 degrees

Answer 2

Sum of (interior) angles in any triangle =180
x+13+144 =180
x + 157 =180
x=180-157
x= 23⁰

Yes, missing angle = 23⁰.