Examine the diagram. It is not drawn to scale.

A triangle has angles 28 degrees, A, C. The exterior angle to the angle with a measure of 28 degrees is D, the exterior angle to angle A is B, the exterior angle to angle C is 125 degrees.

Choose the equation that cannot be used to find the measure of angle B.
m∠B = m∠C + 28°.
m∠B = 360° – (m∠D + 125°).
m∠B = 180° – m∠A.
m∠B = m∠D + 125°.