The Formula Triangle
The formula triangle is a memory tool. Click a variable to reveal how to calculate it.
👆 Click D, S, or T above to see the formula
How to use the triangle:
Cover the value you want to find with your finger. What remains shows you the formula to use.
For example, cover D and you see S × T — so Distance = Speed × Time.
Calculator — Choose What to Find
Select what you want to calculate, then enter the two known values.
📋 Step-by-Step Working
Watch It Move!
After you calculate, press Play to see the car travel — faster or slower depending on your speed.
Complete a calculation above, then press Play.
Time Conversion Helper
Speed formula questions use decimal hours, not hours and minutes. Convert here, then copy the decimal into the calculator above.
Quick examples — click to fill:
Practice Questions
Choose a difficulty level, answer each question, then click Check for instant feedback and worked solutions.