year 8 maths

3C
Area
135
13 Write down expressions for the area of these shapes in simplest form using the letters a and b
(e.g. A = 2ab + a 2 ).
a
2b
b
c
a
a
b
b
a
b
14 Using only whole numbers for length and breadth, answer the following questions.
a How many distinct (different) rectangles have an area of 24 square units?
b How many distinct squares have an area of 16 square units?
15 Write down rules for:
a the breadth of a rectangle (b) with area A and length l
b the side length of a square (l) with area A
c the height of a triangle (h) with area A and base b
ENRICHMENT
– –
16
The acre
16 Two of the more important imperial units of length and area that are still used today are the mile
and the acre. Many of our country and city roads, farms and house blocks were divided up using
these units.
Here are some conversions:
1 square mile = 640 acres
1 mile ≈ 1.609 344 km
1 hectare = 10 000 m 2
a Use the given conversions to find:
i the number of square kilometres in 1 square mile (round to two decimal places)
ii the number of square metres in 1 square mile (round to the nearest whole number)
iii the number of hectares in 1 square mile (round to the nearest whole number)
iv the number of square metres in 1 acre (round to the nearest whole number)
v the number of hectares in 1 acre (round to one decimal place)
vi the number of acres in 1 hectare (round to one decimal place)
b A dairy farmer has 200 acres of land. How many
hectares is this? (Round your answer to the nearest
whole number.)
c A house block is 2500 m 2 . What fraction of an acre
is this? (Give your answer as a percentage rounded
to the nearest whole number.)
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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