# ISEE Upper Level Math : How to find an angle in other quadrilaterals

## Example Questions

### Example Question #1 : Other Quadrilaterals

Three of the interior angles of a quadrilateral measure  , and . What is the measure of the fourth interior angle?     Explanation:

The measures of the angles of a quadrilateral have sum . If is the measure of the unknown angle, then:    The angle measures .

### Example Question #2 : Other Quadrilaterals

The angles of a quadrilateral measure . Evaluate .     Explanation:

The sum of the degree measures of the angles of a quadrilateral is 360, so we can set up and solve for in the equation:      ### Example Question #3 : Other Quadrilaterals

The four angles of a quadrilateral have the following value: 79 degrees, 100 degrees, 50 degrees, and degrees. What is the value of ?     Explanation:

Given that there are 360 degrees when all the angles of a quadrilateral are added toghether, this problem can be solved with the following equation:    ### Example Question #4 : Other Quadrilaterals

In a quadrilateral, the angles have the following values: What is the value of ?     Explanation:

Given that there are 360 degrees when the angles of a quadrilateral are added together, it follows that:     