Angles in Quadrilaterals Worksheets - Free Printable

- First, look closely: The image is a worksheet titled "Quadrilateral - Angles" with nine problems (labeled 1 through 9). Each problem shows a quadrilateral with some of its interior angles given as numerical values or algebraic expressions (e.g., 'x', '2x'). The task is to find the measure of the indicated angle, which is marked with a variable like 'x' or 'y'. The fundamental principle for solving these is that the sum of the interior angles of any quadrilateral is always 360 degrees. I need to set up an equation for each problem where the sum of all four angles equals 360 and solve for the unknown variable.

- Next, find information: I will now solve each of the nine problems individually using the rule that the sum of the interior angles of a quadrilateral is 360 degrees.

- Then, review the findings: I have calculated the value for each indicated angle based on the provided information in the image.

1. x = 85
2. x = 70
3. x = 40
4. x = 80
5. x = 75
6. x = 100
7. x = 70
8. x = 80
9. y = 55