What is the sum of the interior angle measures in quadrilateral?

Answer 1

If it is a regular quadrilateral, or any other shape you will subtract 2 from the sides.

example: 5 sides - 2 = 3

4 sides - 2 = 2 < use for quadrilateral

Then you will multiply the difference by 180.

example: 3 x 180 = 540

2 x 180 = 360 < use for quadrilateral

This is the total sum of all the angles. Now to find each angle measurement divded this product by the amount of sides.

example: 540 / 5 = 108

360 / 4 = 90 < use for quadrilateral

This is because subtracting in the begininng will show how many triangles are in the shape. One triangle equals 180 degrees, that's why you multiply. You divid if you don't know each angle measurement.

I hoped it help :)