A restaurant prices its round pizzas in direct proportion to their area. A pizza of diameter 20 cm costs ₹300. What does a pizza of diameter 30 cm cost?

Explanation

1. 01

   Area varies as the square of the diameter.

2. 02

   Price ratio = $\left(\frac{30}{20}\right)^2 = \frac{9}{4}$.

3. 03

   Price = ₹300 × $9/4$ = ₹675.