Question

find the fourth proportional in each of the following: 1/2,1/3,1/4​

Answer 1

Step-by-step explanation:

Given terms are 1/2,1/3,1/4

Let the fourth proportional be X

=>1/2:1/3::1/4:X

Product of extremes=X/2

Product of means=1/3×1/4=1/12

We know that

Product of means=Product of extremes

=>X/2=1/12

=>X=(1/12)×2

=>X=1/6

The fourth proportional=1/6

Answer 2

$\rm{\dfrac{1}{2}:\dfrac{1}{3}::\dfrac{1}{4}:a}$

• Product of Means = Product of Extremes

⇒ $\rm{\dfrac{1}{3}\times \dfrac{1}{4}=\dfrac{1}{2}\times a}$

⇒ $\rm{\dfrac{1}{12}=\dfrac{a}{2}}$

• Cross Multiply

⇒ $\rm{2=12a}$

⇒ $\rm{a=\dfrac{2}{12}}$

⇒ $\rm{a=\dfrac{1}{6}}$