Ihave to use the pythagorean theorem for this but idk how to do that with four numbers

Step-by-step explanation:

Remark

Simple you can't. I mean that you can't try to use 4 numbers, but you can solve the problem. You are going to have to redraw the diagram on another sheet of paper. Follow the directions below.

Directions for diagram extension.

Go to the right hand end of the 10 unit line.

Draw a line from the intersection point of the 10 unit line and 12 unit line

Draw this line so it is perpendicular to the 18 unit line. That will mean that the new line is parallel (and equal) to x

Mark the intersect point of the new line and the 18 unit line as B

Mark the intersect point of the 18 point line and the 12 unit line as C

Given and constructed

BC = 18 - 10 = 8

BC is one leg of the Pythagorean triangle.

The new x is the other leg of the Pythagorean triangle.

12 is the hypotenuse.

Formula

x^2 + 8^2 = 12^2

x refers to the new x which is equal to the given x

Solution

x^2 + 64 = 144              Subtract  64 from both sides

x^2 +64 - 64 = 144-64  Combine

x^2 = 80                        Break 80 down.

x^2 = 4 * 4 * 5               Take the square root of both sides        

x = 4*sqrt(5)

Comment

If you want the area it is 4*sqrt(5)(10 + 18)/2 = 56*sqrt(5)