# Video: AQA GCSE Mathematics Higher Tier Pack 1 β’ Paper 1 β’ Question 8

AQA GCSE Mathematics Higher Tier Pack 1 β’ Paper 1 β’ Question 8

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### Video Transcript

π gallons is equal to π liters. Using the fact that 4.5 liters is equal to one gallon, write a formula for π in terms of π.

It might help to think of this a little bit like a ratio. The ratio of π to π is one to 4.5. For every one gallon, we have 4.5 liters.

To create a formula for π in terms of π, weβre going to divide. Weβre going to divide π, the number of gallons, by π, the number of liters. Here, thatβs one divided by 4.5.

Now, 4.5 as a denominator of a fraction isnβt particularly nice. So weβre going to double. Weβre gonna multiply it by two, both the numerator and the denominator of this fraction. And doing so, we get π over π is the same as two-ninths.

Next, weβre going to multiply both sides of this equation by π. Remember weβre trying to make π the subject. And at the moment, π is being divided by π. The opposite of dividing by π is multiplying by π. And that tells us π is equal to two-ninths multiplied by π.

Our formula for π in terms of π is π is equal to two-ninths π.