A ratio is equal to 3 : 4. If its consequent is 144, what is its antecedent?

Let the antecedent be x. Then,

3 : 4 = x : 144

$\Rightarrow \dfrac{3}{4} = \dfrac{x}{144} \\[1em] \Rightarrow 3 \times 144 = 4x \\[1em] \Rightarrow 432 = 4x \\[1em] \Rightarrow x = \dfrac{432}{4} \\[1em] \Rightarrow x = 108$

Hence, the antecedent = 108.