Could you state the whole question word for word?
What is tangent to what now? This is the part you need to clarify.A circle contains two vertices of a square and is tangent to the opposite side.
A circle contains two vertices of a square and is tangent to the opposite side. If each side of the square has length 10, find the radius of the circle. Write your answer as a simplified common fraction.
Could I get an answer, and if possible, a picture?
Consider the square with vertices: (0,0), (10,0), (10,10), & (0,10).
Now you should know how to find the equation of a circle determined by three non-collinear points. So do that for the points (0,0), (0,10), & (10,5).
Actually it made sense the first time.