year 8 maths

3L
Using Pythagoras’ theorem
179
Exercise 3L
UNDERSTANDING AND FLUENCY
1–5 3, 4–5(½)
4–5(½)
1 Decide if these numbers written with a √ sign simplify to a whole number. Answer yes or no.
a √9 b √11 c √20 d √121
2 Round these surds correct to two decimal places, using a calculator.
a √10 b √26 c √65 d √230
3 Write Pythagoras’ theorem for each of the following triangles.
a
b
w
7
c
3
8
5
x 9
m
8
d
7
x
9.4
Example 25a
4 Find the length of the hypotenuse (c) of these right-angled triangles.
a
b
24 c
3
c
c
4
7
9
c
40
d
c 16
e
c
36
f
c
60
11
12
27
Example 25b
5 Find the length of the hypotenuse (c) of these right-angled triangles, correct to two decimal places.
a 7
b
5
c
c
6
2 4
c
c
4
d
e
f 19
3 1
2.5
c
c
c
32
3.5
PROBLEM-SOLVING AND REASONING
6, 7, 10 7–10
7–11
Example 26
6 A r ectangular board is to be cut along one of its diagonals. The board is 3 m wide and 1 m high.
What will be the length of the cut, correct to the nearest cm?
1 m
3 m
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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