If you know any two of distance, speed, and time, you can always find the third. Put distance at the top of the triangle, speed and time in the two lower cells, then cover the quantity you want to find to reveal whether to multiply or divide.
Cover the quantity you want to find, and the positions of the remaining two cells tell you whether to multiply or divide
How to read the triangle: To find distance, cover the "Distance" cell. If the remaining "Speed" and "Time" cells are side by side, multiply → Distance = Speed × Time.
To find speed, cover the "Speed" cell. If "Distance" is above "Time," divide → Speed = Distance ÷ Time. The same method gives Time = Distance ÷ Speed.