Head First 2D Geometry

Mar

io will

add 5 c

ents

p

er p

i

ece of

p

epp

eroni.

custom sized pies

Pepperoni crust pizza—but at what price?

Mario’s idea is to offer a pepperoni crust on any pizza. He wants to offer

the best possible value to his customers so he’ll only add the minimum

price needed to cover the cost of the extra pepperoni. Sounds simple,

right? But Mario has a problem with the sequence of events in the pizza

process:

1

The customer rings up with their order.

2

Mario says how much it will be.

That’s 12

dollars and

60 cents.

3

Mario makes the pizza.

I’d like a 14"

Hawaiian, with

pepperoni crust.

The catch is…Mario’s pizzas are custom sized!

If Mario only offered a couple of pizza sizes you could just make

the crust for each size once and then always add the cost of that

amount. But Mario likes to give his customers as much choice as

possible.

212 Chapter 5

I let the customer choose the size

they want—any size—8-inch, 23-inch,

whatever. But to give them the right

price I need to know now many pieces of

pepperoni I’ll use on the edge—before I

make the pizza! Is this possible?

circles

Geometry Detective

Mario needs a way to work out how many pieces of pepperoni it will

take to edge a pizza, based only on the diameter of the pizza. Each

piece of pepperoni is 1 inch across.

Your mission is to investigate the relationship between the diameter

of each pizza and the “perimeter,” or outside edge, of the pizza. How

many pieces of pepperoni does Mario need to edge each pizza

below? Is there a pattern?

Scale: 1cm = 2 inches

Hint: A piece of string can be useful

to measure the outside edge of a

circle

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