OK, y

ou could kind of nibble the

circumf

er

ence if y

ou w

anted....

compare areas

What property of the pizzas do you need to compare to be able to

work out whether MegaSlice’s claims are true?

Area

If you put “V

olume” her

e, you’r

e right,

but as all Mar

io’s p

izzas hav

e the same

thickness, ar

ea will also cov

er i

t. Mor

e on

tha

t in C

hapter 7!

We need to find the area of the two pizza deals

MegaSlice offers two 12" pizzas for the same price as one of

Mario’s 18" pizzas.

So, which deal is more AREA of pizza, because that’s the

property you actually get to eat.

W

hich is mor

e?

18"

12"

12"

224 Chapter 5

circles

Well, I’m not sure we even need

to work this one out. Two times

twelve is more than eighteen, so

MegaSlice’s deal is more pizza.

Frank: Not so fast. I’m not sure it’s that simple.

Joe: What’s hard about it? 12 + 12 = 24. 24 is way more

than 18. Game over.

Jim: But that’s not area—that’s diameter!

Joe: Yeah—and?

Jim: Well, I’m not sure that you can just add up diameters

and then compare them instead of comparing area.

Joe: Why not? Anyway, we don’t even know how to find

the area of a circle. Hey—is this making you guys hungry?

Frank: Shut up! This is serious. We need to find a way to

compare the actual pizza area, and not just the diameters.

Jim: Agreed, but where do we start?

Frank: Well, I guess we should just start from what we do

know and go from there.

Which technique from your Geometry Toolbox could help you

work out the pizza areas approximately?

T

r

iangle ar

ea

= 1/2 base x

height

Simil

ar

i

ty and

congruenc

e

Angles in a

quadr

ila

tera

l

add up t

o 360º.

Frank

Jim

Joe

you are here 4 225

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