Equations

Question 1

What is the equation to find the area of a rectangle?

Answer 1

Area = length x width
A = lw

Question 2

What is the equation to find the area of a triangle?

Answer 2

Area = 1/2 x base x height
A = 1/2bh

Question 3

What is the equation to find the area of a parallelogram?

Answer 3

Area = base x height
A = bh

Question 4

What is the equation to find the area of a trapezium?

Answer 4

Area = 1/2(a + b) x height
A = 1/2(a + b)h

Question 5

What is the equation to find the circumference of a circle?

Answer 5

Circumference = π x diameter
C = πd

Question 6

What is the equation to find the area of a circle?

Answer 6

Area = π x radius2
A = πr2

Question 7

What is the equation to find the volume of a prism?

Answer 7

Volume = area of cross section x height
V = area of cross section x h

Question 8

What is the equation to find the volume of a cylinder?

Answer 8

Volume = π x radius2 x height
V = πr2h

Question 9

What is the equation to find the volume of a pyramid?

Answer 9

Volume = 1/3 x area of base x height
V = 1/3 x area of base x h

Question 10

What are the three equations for Pythagoras’ theorem?

Answer 10

c2 = a2 + b2
b2 = c2 - a2
a2 = c2 - b2

Question 11

What is the cosine rule for sides?

Answer 11

a2 = b2 + c2 - 2bc x cosA

Question 12

What is the cosine rule for angles?

Answer 12

A = cos-1(b2 + c2 - a2) /2bc))

Question 13

What are the three equations for the trigonometric ratios?

Answer 13

sinθ = opposite / hypotenuse
cosθ = adjacent / hypotenuse
tanθ = opposite / adjacent

sinθ = opp / hyp
cosθ = adj / hyp
tanθ = opp / adj

Question 14

What is the sine rule for sides?

Answer 14

a/sinA = b/sinB = c/sinC

Question 15

What is the sine rule for angles?

Answer 15

sinA/a = sinB/b = sinC/c

Question 16

What is the equation to find the area of a triangle? (Trigonometry)

Answer 16

Area = 1/2 x a x b x sinC
A = 1/2absinC

Question 17

What is the quadratic formula?

Answer 17

x = (-b ± √b2 - 4ac) /2a)

Question 18

What is the equation for the probability “and” rule?

Answer 18

P(A or B) = P(A) + P(B) - P(A and B)

Question 19

What is the equation for the probability “or” rule?

Answer 19

P(A and B) = P(A given B) P(B)

Question 20

What is the equation for compound interest?

Answer 20

Total = P(1 + r/100)^n

Question 21

What is the equation for simple interest?

Answer 21

A = Prt
A P(1 + rt)

Question 22

What is the equation for percentage change?

Answer 22

Percentage change = different / original
Pc = diff/orig

Question 23

What is the equation to find the gradient?

Answer 23

Gradient = change in y / change in x
G = change in y / change in x

Question 24

What is the equation to find the sum of interior angles in a polygon?

Answer 24

Sum of interior angles = 180(n-2)

Question 25

What are the three equations to find speed, distance, and time?

Answer 25

Speed = distance / time
Distance = speed x time
Time = distance / speed

S = d / t
D = st
T = d / s

Question 26

What are the three equations to find mass, density, and volume?

Answer 26

Density = mass / volume
Mass = density x volume
Volume = mass / density

D = m / v
M = dv
V = m / d

Question 27

What are the three equations to find flow rate, time taken, and volume?

Answer 27

Flow rate = change in volume / time taken
Time taken = volume / flow rate
Volume = flow rate x time taken

fr = change in volume / tt
tt = v / fr
v = frtt

Question 28

What are the three equations to find flow rate, time taken, and volume?

Answer 28

Flow rate = change in volume / time taken
Time taken = volume / flow rate
Volume = flow rate x time taken

fr = change in volume / tt
tt = v / fr
v = frtt

Question 29

What is the equation for direct proportion?

Answer 29

y = kx

Question 30

What is the equation for inverse proportion?

Answer 30

y = k/x

Question 31

What is the equation for the product rule for counting?

Answer 31

n(n - 1)

n(n - 1) /2

Question 32

What is the equation for exponential growth?

Answer 32

y = A x 2^x

Question 33

What is the equation for exponential decay?

Answer 33

y = A x 3^-x

Question 34

What are the three equations to find frequency density, frequency, and class width?

Answer 34

frequency density = frequency / class width
frequency = frequency density x class width
class width = frequency / frequency density

fd = f / cw
f = fdcw
cw = f / fd