triangle properties

Fencing costs money

To make sure that only the people who’ve bought a ticket for your

festival can come in, you’re going to need to set up a security fence

around the perimeter. And that’s not cheap! The cost of setting up

the security fence will be different for each potential venue.

$15

90m

60m

Field A

80m

85m

85m

Field B

42m

33m

33m

60m

60m

Field C

you are here 4 153

Work out what it would cost to put up a security fence around each venue.

(Fencing costs $15 per meter—work by rounding UP to a whole meter.)

Use a ca

lcul

a

t

or

because the number

s

get a bi

t ugl

y.

field C is the cheapest

154 Chapter 4

3364 +

Rounded up t

o the nex

t meter—

can’t buy a bi

t of a f

enc

e panel!

Work out what it would cost to put up a security fence around each venue. (Fencing costs $15

per meter—work by rounding UP to a whole meter.)

60m

Field A

For field A we need to use the Pythagorean

Theorem to find the missing side (the hypotenuse).

H

2

= 60

2

+ 90

2

H

2

= 3600 + 8100

H

2

= 11700

H = 11700

H = 108.16 = 109m

H

Perimeter, P = 60 + 90 + 109

P = 259m

Don’t f

orget y

our uni

ts.

Field B

80m

85m85m

Field C

42m

33m

33m

60m

60m

Perimeter, P = 80 + 85 + 85

P = 250m

Perimeter, P = 60 + 60 + 33 + 33 + 42

P = 228m

Cost = 259 x 15 = $3885

Cost = 250 x 15 = $3750

Cost = 228 x 15 = $3420

F

i

eld A is a

r

ight tr

iangle.

T

his one is the cheap

es

t.

90m

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