What is the length of the longest side of a triangle that has the vertices (-3, 1), (5, 1), and (5, 6)?

There are 15 plates and each plate is either 7 or 12 inches diameter. which systems of equations do you use to find the number of 7 inch plates, x and 12 inch plates, y

Can you me find the missing length. i attached an image.

Suppose that 15 inches of wire cost 60 cents. at the same rate, how much (in cents) will 12 inches of wire cost