Final answer:
The sum of the angles in a trapezoid is 360 degrees. To find a missing angle, subtract the sum of the known angles from 360 degrees. If three angles are known, the fourth can be easily calculated.
Step-by-step explanation:
The student's question pertains to the properties of a trapezoid, specifically the sum of its angle measures. The sum of the angles in any quadrilateral, including trapezoids, is 360 degrees. If a student wishes to find a missing angle measure, they must first know the measures of the other three angles. Once these are known, they can subtract the sum of the known angles from 360 degrees to find the missing measure.
For example, if the known angles are 90 degrees, 110 degrees, and 70 degrees, we add these to get 270 degrees. Then we subtract this sum from the total sum of angles in a quadrilateral, which is 360 degrees, to find the missing angle: 360 degrees - 270 degrees = 90 degrees. Therefore, the missing angle measure is 90 degrees.