posted by Beth .
Two spaceships A and B are exploring a new planet. Relative to this planet, spaceship A has a speed of 0.54c, and spaceship B has a speed of 0.74c. What is the ratio DA/DB of the values for the planet's diameter that each spaceship measures in a direction that is parallel to its motion?
I keep getting 1.37 which is the incorrect answer. I understand in general how to do the problem, but I must be missing a step