Step 1 :Assume the figure is a triangle with angles A, B, and C. The sum of angles in a triangle is 180 degrees: \(A + B + C = 180^\circ\)
Step 2 :Given options for the unknown angle are 70, 120, 290, and 360 degrees. Check each option to see if it makes the sum of angles in the triangle equal to 180 degrees.
Step 3 :\boxed{70^\circ} is the correct measurement of the unknown angle in this figure.