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Garden perimeters ' • Garden ponds • • II a • • •
[iJ Find the totol distonce around each of these gardens.
Show your workings-out. The Frasers are designing a square garden pond.
They are planning to lay square slabs
with sides 1 m long around the pond's perimeter.
[j] If the pond is 6m by 6m,
how many slabs will they need?
Some slabs have been drown
in place on the diagram.
0 Copy and complete this table
for square ponds of different sizes.
length of each number of
side of pond slobs needed
1m
2m
3m
Sm
P= 2(1+ b) 6m
=2(7+5)m
=2(12)m []J
W Check your answers to[!] =24m Using the pattern inW, decide how many slabs would be needed
using this formula. for square ponds with sides these lengths.
P represents perimeter.
Does the formula work I represents length. a 10m b 20m
for every example? Explain how you worked out your answers.
13]
CHALLENGE Complete this operation box so that it gives the correct output for any input.
• Using the formula, work out the perimeters of these patios.
9·0m
,.1•:~~1 , .. J"~il' ~I r CHALLENGE SOcm '
•How many of slab A would you need to cover .socm
• A garden centre stocks edging strips in 60 cm and 90 cm lengths.
the same area as the 1 m slabs around the pond in m?
• Investigate which length of strips will give the best fit for each patio. II
• Show how you work out your answers.
• Drow a pion to show how the lengths of edging fit around each patio. •What if you used slab B? • 2 cm
5
• Decide what you would order for patio A and for patio B. ~ U=
rn
a (4·8m + 7·3m) x 2 = 12·1mx2 = 24·2m Practical: check the 28 slabs x 4 + 4
b (3· 1 m + 8·2 m) x 2 = 11 ·3 m x 2 = 22·6 m answers using the
formula P = 2(/ x b). Challenge
c (q m + 5 m) x 2 = 14 m x 2 = 28 m
d (6 m + 7 m) x 2 = 13 m x 2 = 26 m Slab A=
length of each number of 2
e (4·5 m + q.5 m) x 2 = 14 m x 2 = 28 m side of pond slabs needed 0·5m x 0·5m = 0·25m
2
2
1 m + 0·25 m = 4
f (4 m + 3·5 m) x 2 = 7·5 m x 2 = 15 m
lm 8 You would need four times as many
slabs to cover the same area.
Challenge 2m 12 4 x 28 = 112 slabs
Patio A: 2 (6 + 3)m = 2(q) m = 18m Patio B: 2 (q + 4·5)m = 2 (13·5)m = 27m 3m 16 Slab B =
60 cm strips will fit Patio A best because both the breadth and the width 4m 20 0·25 m x 0·25 m = 0·0625 m 2
2
2
are exactly divisible by 60 cm. Sm 24 1m +0·0625m = 16
qo cm strips will fit Patio B best because both the breadth and the width You would need 16 times as many
are exactly divisible by qo cm. 6m 28 slabs to cover the same area.
16 x 28 = 448 slabs
Practical: draw a plan showing how the lengths fit around each patio.
You would need to order 30 of the 60 cm strips for Patio A.
You would need to order 30 of the qo cm strips for Patio B. a 44 slabs b 84 slabs