Question

How do you solve `\frac{3}{4} = \frac{42}{x}`?

Answer 1

`x=56`

Explanation:

There are a couple of ways to do this.

The first is to notice that 3 is a factor of 42: `3xx14=42`. So we can multiply 4 by 14 to get `x=56`.

We can also solve using cross multiplication. We do this by multiplying the both sides by the denominator and having them cancel out on one side. It looks like this:

`3/4=42/x`

`3/4(4)(x)=42/x(4)(x)`

`3/cancel4(cancel4)(x)=42/cancelx(4)(cancelx)`

`3(x)=42(4)`

`3x=168`

`x=56`