Hello!
It looks like we only have one angle measurement and one side measurement.
But this is not true!
You'll notice, by the square, this is a right triangle!
Right triangles have a 90 degree angle.
That means we have two angle measurements!
But now what?
If we add them together, we'll get a number we can subtract from 180 (the total degree measure of any triangle).
180-120 =60
That means the last angle is 60 degrees!
Now we have all three angles.
But what about the sides?
We have enough information to figure out the sides.
I will use geogebra to make the nine-unit line, and create an angle by making two points, one ninety degrees clockwise, and the other sixty. Then, I used the line tool to extend the lines and marked the points of intersections with the intersect tool. Everything checks out, the angles are correct! FInally, I use a measure tool to measure the segments created by intersections that make the triangle. (NOTE THAT THE TRIANGLE WAS FLIPPED WHEN I MAPPED IT)
y = (rounded up) 16, look a diagram
x = 18
I can check it using the Pythagoreas theorem!
9^2+16^2
81 + 256= 337
The square root of 337 is about 18!
Because this is not totally exact, be sure to use a formula to get the true answer!