Question

Find $$x$$, when $$1:3::x:7$$.

Answer 1

We use the property: $$\text{Product of extremes} = \text{Product of means}$$.

$$1 \times 7 = 3 \times x$$

$$3x = 7$$

$$x = \frac{7}{3} = 2\frac{1}{3}$$