Solve for x! It's for circles, and I don't understand how to figure it out. So if someone could help, that would be great!

  x = 5

Step-by-step explanation:

The only thing the circle does for you is tell you that the angle between the lines marked 3 and 4 is a right angle. A tangent line is always at right angles to the radius at that point.

So, you have a 3-4-x right triangle. The Pythagorean theorem applies:

  3² +4² = x²

  9 + 16 = x² = 25

  x = √25

  x = 5

Comment on the answer

This is a 3-4-5 right triangle. You will meet them a lot, so it is useful to remember these side ratios form a right triangle.