During the basketball game josh devon and marco are in the following positions josh is 16 feet from devon and devon is 5 1/3 feet from marco if marco is 4 feet from both a and b how wide is the key i am in prealgebra and this problem has been difficult for me i don't even know we're to start

First off, actually including the diagram is required if you intend on getting an answer. Thankfully, someone else has posed this question on another site and actually included the diagram. I will first describe the diagram, and then solve the problem.
And the good news is
The triangle in the diagram is impossible.

The diagram I found has Josh, Devon, and Marco standing creating an isosceles triangle with Josh and Devon forming the base. And with the given measurements, the illustrated triangle is impossible since in order for form an isosceles triangle with a base of 16 feet (the distance between Josh and Devon), each leg of the triangle would have to be at least 8 feet long and the specified 5 1/3 feet is way too short. So the actual triangle created by Josh, Devon, and Marco can't be an isosceles triangle. But the triangle created by Marco and points A and B has to be an isosceles triangle since the distance from Marco to both points A and B is 4 feet. Therefore we can prove that the two triangles are NOT similar. And therefore using the constant ratio between similar sides of the triangles can not apply.