How to find volume of a rectangular prism ith surface area, width and length but no height

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

The length of triangle base is 26. a line, which is parallel to the base divides the triangle into two equal area parts. find the length of the segment between triangle legs.

The vertices of a triangle are a(7.5), b(4,2), and c19. 2). what is