Maths Formula

Question 1

Area of a trapezium

Answer 1

A = 1/2 ( a + b) h

Question 2

Volume of prism

Answer 2

area of cross section x depth

Question 3

exterior angle formulae

Answer 3

exterior angle = 360°/ n

n = Number of angles

Question 4

sum of interior angles in a n-sided polygon

Answer 4

sum of interior angles = ( n - 2 ) x 180°

n = Number of angles

Question 5

Percentage increase

Answer 5

Percentage increase = (new amount - original / original amount) x 100

Question 6

Percentage decrease

Answer 6

Percentage decrease = (actual decrease / original amount) x 100

Question 7

Volume of a pyramid

Answer 7

1/3 x area of base x h

Question 8

Percentage profit

Answer 8

Percentage profit = (profit / cost price) x 100

Question 9

Percentage loss

Answer 9

Percentage loss = (loss / cost price) x 100

Question 10

Simple interest

Answer 10

I = (P x R x T) / 100

I = Simple interest
P = Principal
R = Rate
T = Time or duration

Question 11

Surface area of a sphere

Answer 11

SA = 4πr^2

SA = Surface Area
^2 = Squared

Question 12

Volume of a sphere

Answer 12

V = 4/3πr

V = Volume
r = Radius

Question 13

Surface area to volume ratio

Answer 13

SA:V = surface area / volume

SA = Surface Area
V = Volume

Question 14

Trigonometric ratios

Answer 14

(SOH) sin x° = o/h
(CAH) cos x° = a/h
(TOA) tan x° = o/a

o = Opposite (to the right angle)
a = Adjacent (to the right angle)
h = Hypotenuse (longest side)

Question 15

Area of a parallelogram

Answer 15

A = b x h

A = Area
B = Base
H = Height

Question 16

Quadratic Forumula

Answer 16

x = (-b ±√b^2 - 4ac) / 2a

± = + or -
√ = Square Root

A quadratic equation is a second order equation written as ax2 + bx + c = 0 where a, b, and c are coefficients of real numbers and a ≠ 0.

Question 17

Pythagoras Theorem (Right angled triangles)

Answer 17

a^2 + b^2 = c^2
c^2 - a^2 = b^2
c^2 - b^2 = a^2

a or b = Lines adjacent to right angle
c = Hypotenuse
^2 = Squared

Question 18

Sine rule

Answer 18

a/Sin A = b/sin B = c/Sin C

Question 19

Area of circle

Answer 19

A = πr^2

A = Area
r = Radius
^2 = Squared

Question 20

Volume of a cone

Answer 20

V = 1/3πr^2h

V = Volume
r = Radius
^2 = Squared
h = Height

Question 21

Standard deviation

Answer 21

σ = sqrt( Σ (X - x̄)² / n-1)

Σ = summation
x̄ = mean of data set
X = data point
n = amount of data points

Question 22

Angle in degrees of a linear function relative to the x-axis

Answer 22

θ = tan^-1(m) * 180 / π

m = gradient