Question

How do I set up an equation to find x for this problem?

Answer 1

x + x + 25 + 2x + 2x - 5 + 6x - 10 + 5x + 10 + 3x = 900

Explanation:

First you have to find the sum of all angle measures. Use the following formula.

S = (n-2) x 180°

S: sum of angle measures

n = number of sides

S = (7 - 2) x 180°

S = 5 x 180°

S = 900°

Now you can setup the equation you need to solve for x by adding all of the angle measures together.

x + x + 25 + 2x + 2x - 5 + 6x - 10 + 5x + 10 + 3x = 900

Answer 2

x + (x + 25) + 2x + (2x - 5) + (6x - 10) + (5x + 10) + 3x


20x + 20 = 900 (Sum of interior angles is 900)
20x = 880
x = 44