Robert has a flat screen TV but doesn't know the size of the screen, which is the diagonal length of the screen. Robert makes a grid with 1 inch × 1 inch squares and places the left bottom corner of the TV at the origin of the grid (0, 0). The left bottom corner of the screen L is located at (3, 5) on the grid and the right top corner of the screen R is located at (15, 14) on the grid. What size TV does Robert have?
