Question

the NACI cafeteria wants to sell two 25 cm diameter medium size pizzas for the same price as one large pizza. what should the diameter be of the large pizza so that it contains the same amount of pizza as the two medium-size pizzas?​

Answer 1

35.34 centimeters

Explanation:

The amount of pizza is same as the area. The pizza is in a shape of a circle. The area of a circle is:

`A=\pi r^2`

Where

r is the radius (half of diameter)

Area of one medium size pizza is (diameter 25 means radius is 25/2 = 12.5):

`A=\pi r^2\\A=\pi (12.5)^2\\A=490.87`

So, area of two of these medium size pizzas is:

490.87 * 2 = 981.74

This should be the area of the large pizza. We can find the radius of that by substituting into formula. Shown below:

`A=\pi r^2\\981.75=\pi r^2\\r=\sqrt{(981.74)/(\pi)} \\r=17.67`

Hence, the diameter would be around:

17.67 * 2 = 35.34 centimeters