year 8 maths

Chapter summary
189
Perimeter
Triangle
Quadrilaterals
4 cm
– Square A = s
3 cm
2
– Rectangle A = lb
10 cm
6 cm
– Parallelogram A = bh
P = 2 × 10 + 2 × 4
1
1
– Rhombus A = xy
= 28 cm
A = bh
2
1
2
– Kite A = xy
1
2
= × 6 × 3
1
2
– Trapezium A = h(a + b)
= 9 cm 2
2
Units
1 km = 1000 m
Circle
Units
1 m = 100 cm
A = πr
×1000 2
1 cm = 10 mm
2 ×100 2 ×10 2
= π × 7 2 7 cm
km 2 m 2 cm 2 mm 2
= 49π cm 2
÷1000 2 ÷100 2 ÷10 2
Circumference
1 ha = 10 000 m 2
Sector
C = 2πr or πd
θ
A = ×πr
= 2 × π × 3
360
2
= 6π m 2 2 m
=
280
3 m
Area
360 × π × 22 280°
= 9.77 m 2
Chapter summary
Length
Measurement
and
Pythagoras’ theorem
Volume
Time
Units
km 3 , m 3 , cm 3 , mm 3
1 min = 60 s
1 h = 60 min
0311 is 03:11 a.m.
2049 is 08:49 p.m.
Pythagoras’ theorem
×1000 ×1000 ×1000
ML kL L
÷1000 ÷1000 ÷1000
1 mL = 1 cm 3
1 m 3 = 1000 L
mL
Theorem
a
c
b
a 2 + b 2 = c 2
Finding c
c 2 = 5 2 + 7 2
= 74
∴ c = √ — 74
7
c
5
Rectangular prism
V = lbh
= 10 × 20 × 30
= 6000 cm 3
= 6 L
30 cm
20 cm
10 cm
Prism and cylinders
V = Ah
V = πr 2 h
1
= × 3 × 1 × 2 = π × 2 2 × 6
2
= 3 m 3 = 75.40 cm 3
2 cm
2 m
3 m
6 cm
1 m
A shorter side
a
a 2 + 1 2 = 2 2 1
a 2 + 1 = 4 2
a 2 = 3
a = √ – 3
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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