Question

If 12 inches correspond to 30.48 cm, then 30 inches correspond to how many inches?

Answer 1

Let 30 inches correspond to x cm.

Inches	Centimeters
12	30.48
30	x

Inches and centimeters are in direct variation.
So, using arrow method:
$\frac{30}{12}=\frac{x}{30.48}$
On cross multiplication,
$x=\frac{30}{12}\times 30.48=76.2$
So, 30 inches corresponds to 76.2 cm.