The sum of the interior angles of a quadrilateral is 180 degrees. Angle a is n degrees, the measure of angle b is four times angle a, and angle c is 75 degrees. Write an equation to determine the value of n.

Answer: the equation to determine the value of n is 5n = 105

Step-by-step explanation:

The measure of angle a is n degrees. The measure of angle b is four times angle a. This means that the measure of angle b would be

b = 4n

The measure of angle c is 75 degrees. Since the sum of the interior angles of a quadrilateral is 180 degrees, then the equation to determine the value of n would be

a + b + c = 180

Therefore,

n + 4n + 75 = 180

5n = 180 - 75

5n = 105

n = 105/5

n = 21