# Writing equations from ratios

I can write equations involving ratios.

# Writing equations from ratios

I can write equations involving ratios.

## Lesson details

### Key learning points

- Ratios can be written as fractions.
- A ratio can be used to write an equation.
- This equation is another way of representing how the two quantities are connected.
- Either of the quantities can be the subject.

### Common misconception

When $$x : y$$ are in the ratio 1 : 2 pupils write the equation as $$x = 2y$$

The bar models shown in this lesson can help to support pupils with this.

### Keywords

Ratio - A ratio shows the relative sizes of 2 or more values and allows you to compare a part with another part in a whole.

Coefficient - A numerical coefficient is a constant multiplier of the variables in a term.

Equation - An equation is used to show 2 expressions that are equal to each other.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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## Starter quiz

### 6 Questions

## Exit quiz

### 6 Questions

1 : 4 -

$$y=4x$$

4 : 1 -

$$y={1\over4}x$$

3 : 2 -

$$y={2\over3}x$$

2 : 3 -

$$y=1.5x$$

3 : 5 -

$$y={5\over3}x$$