Formula sheets · Year 8

Year 8 maths formula sheet

Every key formula and rule for Year 8 maths on one printable page, following the Australian Curriculum. Tap any formula to see worked examples on that topic.

Year 8 maths formula sheet

Australian Curriculum · tuterly.com.au/formula-sheets

Number

Index laws
am×an=am+na^m \times a^n = a^{m+n}am÷an=am−na^m \div a^n = a^{m-n}(am)n=amn(a^m)^n = a^{mn}a0=1a^0 = 1
Percentage increase or decrease
new amount == original ×(1±r100)\times \left(1 \pm \dfrac{r}{100}\right)
Profit and loss
profit == selling price −- cost price%\% profit =profitcost price×100%= \dfrac{\text{profit}}{\text{cost price}} \times 100\%
Recurring decimals
13=0.3˙\tfrac{1}{3} = 0.\dot{3}111=0.0˙9˙\tfrac{1}{11} = 0.\dot{0}\dot{9}

Algebra

Expanding brackets
a(b+c)=ab+aca(b + c) = ab + ac−2(x−3)=−2x+6-2(x - 3) = -2x + 6
Linear relationship
y=mx+cy = mx + c((a straight line when graphed))

Measurement

Pythagoras' theorem
c2=a2+b2c^2 = a^2 + b^2(c(c is the hypotenuse))
Circumference of a circle
C=2πr=πdC = 2\pi r = \pi d
Area of a circle
A=πr2A = \pi r^2
Area of a trapezium
A=12(a+b)hA = \tfrac{1}{2}(a + b)h
Area of a rhombus or kite
A=12xyA = \tfrac{1}{2}xy(x,y(x, y are the diagonals))
Volume of a prism
V=A×hV = A \times h(A(A is the area of the cross-section))
Capacity
11 L =1000= 1000 mL, 1, \ 1 kL =1000= 1000 L, 1, \ 1 m3=1000^3 = 1000 L
Speed, distance, time
s=dts = \dfrac{d}{t}d=std = stt=dst = \dfrac{d}{s}
Area units
11 m2=10 000^2 = 10\,000 cm2^211 ha =10 000= 10\,000 m2^2

Space

Congruent triangle tests
SSS, SAS, AAS, RHS
Quadrilateral angle sum
360∘360^\circ

Statistics and probability

Complementary events
P(P(not A)=1−P(A)A) = 1 - P(A)
Mean, median, mode, range
mean =sumcount= \dfrac{\text{sum}}{\text{count}}range == highest −- lowest

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