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Year 11 (GCSE) · Formula sheet

Maths formulas

Everything from Year 10 and before, with the Year 11 formulas marked "New".

Area and perimeter

Rectangle
A = l × w
Triangle
A = ½ × b × h
Parallelogram
A = b × h
Trapezium
A = ½(a + b)h
Circle: area
A = πr²
Circle: circumference
C = πd = 2πr
bah

Volume

Cuboid
V = l × w × h
Prism
V = area of cross-section × length
Cylinder
V = πr²h
Units
1 litre = 1000 cm³1 m³ = 1 000 000 cm³
rh

Pythagoras' theorem and trigonometry

Pythagoras' theorem
a² + b² = c²c is the hypotenuse, the longest side
Sine (SOH)
sin θ = oppositehypotenuse
Cosine (CAH)
cos θ = adjacenthypotenuse
Tangent (TOA)
tan θ = oppositeadjacent
θadjacentoppositehypotenuse

Angles

Angles on a straight line
add up to 180°
Angles around a point
add up to 360°
Angles in a triangle
add up to 180°
Angles in a quadrilateral
add up to 360°
Interior angles of an n-sided polygon
sum = (n − 2) × 180°
Exterior angles of any polygon
add up to 360°
Parallel lines
alternate and corresponding angles are equalco-interior angles add up to 180°

Compound measures

Speed
speed = distancetime
Density
density = massvolume
Pressure
pressure = forcearea

Number

Multiplying powers
aᵐ × aⁿ = aᵐ⁺ⁿ
Dividing powers
aᵐ ÷ aⁿ = aᵐ⁻ⁿ
Power of a power
(aᵐ)ⁿ = aᵐⁿ
Zero and negative powers
a⁰ = 1, a⁻ⁿ = 1aⁿ
Standard form
A × 10ⁿ, where 1 ≤ A < 10
Percentage change
changeoriginal × 100

Graphs and probability

Straight line
y = mx + cm is the gradient, c is the y-intercept
Gradient
m = change in ychange in x
Probability of not happening
P(not A) = 1 − P(A)
Expected frequency
P(A) × number of trials
Independent events
P(A and B) = P(A) × P(B)

Surds

Multiplying
√a × √b = √(ab)
Dividing
√a ÷ √b = √ab
Rationalising
a√b = a√bb
Conjugate pairs
(a + √b)(a − √b) = a² − b

Quadratics

Quadratic formula
x = −b ± √(b² − 4ac)2asolves ax² + bx + c = 0
Completing the square
x² + bx + c = (x + b2)² − (b2)² + c
Difference of two squares
x² − a² = (x + a)(x − a)

Growth and decay

Compound interest
A = P(1 + r100)ⁿ
Depreciation
A = P(1 − r100)ⁿP is the starting amount, r the % rate, n the number of years

Circles, spheres and cones

Arc length
θ360 × 2πr
Sector area
θ360 × πr²
Sphere
V = 43πr³, surface area = 4πr²
Cone
V = 13πr²h, curved surface = πrll is the slant height
Pyramid
V = 13 × base area × h
r

Similar shapes

Lengths
multiplied by k (the scale factor)
Areas
multiplied by k²
Volumes
multiplied by k³
Congruent triangles
SSS, SAS, ASA, RHS

Circle theorems

Angle at the centre
twice the angle at the circumference
Angle in a semicircle
90°
Angles in the same segment
are equal
Cyclic quadrilateral
opposite angles add up to 180°
Tangent and radius
meet at 90°

Vectors, statistics and probability

Magnitude of a vector (x, y)
√(x² + y²)
Interquartile range
upper quartile − lower quartile
Mutually exclusive events
P(A or B) = P(A) + P(B)

Non-right-angled trianglesNew

Sine rule (sides)
asin A = bsin B = csin C
Sine rule (angles)
sin Aa = sin Bb = sin Cc
Cosine rule (side)
a² = b² + c² − 2bc cos A
Cosine rule (angle)
cos A = b² + c² − a²2bc
Area of a triangle
A = ½ab sin CC is the angle between sides a and b
ABCabcABC

Exact trigonometric valuesNew

sin 0°, 30°, 45°, 60°, 90°
0, 12, √22, √32, 1
cos 0°, 30°, 45°, 60°, 90°
1, √32, √22, 12, 0
tan 0°, 30°, 45°, 60°
0, √33, 1, √3

Algebra and graphsNew

Perpendicular gradients
m₁ × m₂ = −1
Circle centre (0, 0)
x² + y² = r²
Iteration
xₙ₊₁ = f(xₙ)
Direct proportion
y = kx or y = kx²
Inverse proportion
y = kx or y = kx²

MotionNew

Velocity-time graph
gradient = acceleration, area = distance
Final velocity
v = u + at
Displacement
s = ut + ½at²
Without time
v² = u² + 2as

Statistics and probabilityNew

Frequency density
frequencyclass width
Either event
P(A or B) = P(A) + P(B) − P(A and B)
Conditional probability
P(A | B) = P(A and B)P(B)