Question

Fill in the blanks.

$40cm:70cm=₹12:₹$___________ .

Answer 1

Finding the missing term in proportion

Proportion :When two ratios are equal in value, then they are said to be in proportion. In simple words, it compares two ratios.

Proportions are denoted by the symbol $‘::’or‘=’$

Let the unknown term be $x$. i.e.

$40cm:70cm=₹12:₹x$

So, $40cm,70cm,₹12$and $₹x$ are in proportion.

$40cm:70cm=₹12:₹x$ can be written as :

$\frac{40cm}{70cm}=\frac{₹12}{₹x}$

$\Rightarrow 40\times x=70\times 12$ (On cross multiplying)

$\Rightarrow 40x=840$

$\Rightarrow x=\frac{840}{40}$ (On transposing $40$ from L.H.S. to R.H.S.)

$\Rightarrow x=21$ (On dividing numerator and denominator by $40$)

Hence, the required term is $₹21$.