formulas

Question 1

Exterior Angles Theorem

Answer 1

a + b + c= 180
x= a + b
c= 180 - x
-exterior angles is equal to sum of opp interior angles

Question 2

formula of exterior angles of regular polygons

Answer 2

360 / n
n = no. sides

Question 3

formula of interior angles of regular polygons

Answer 3

180 ( n -2 )
n = no. sides

Question 4

how to find sum of interior angles in a polygon

Answer 4

-from 1 point draw lines to other points inside the polygon
-180 x no. triangles found

Question 5

formula for sector angle size of pie chart

Answer 5

-sector angle size = fraction x 360
-find fraction by measuring

Question 6

formula for sector no. side of pie chart

Answer 6

-sector no. = fraction x total no.
-find fraction by measuring

Question 7

formula for no. % in pie chart

Answer 7

-no. % = fraction x 100%
-find fraction by measuring

Question 8

formula for mean

Answer 8

add all / no. of things

Question 9

how to find mode/ modal

Answer 9

most occurring value

Question 10

how to find median

Answer 10

rearrange from lowest to highest and find middle value

Question 11

formula for range

Answer 11

highest value - lowest value

Question 12

formula to find % of a no.

Answer 12

a/100 x b

Question 13

formula to find no. from %

Answer 13

% x no.

Question 14

formula for theoretical probability

Answer 14

P(x) = what should happen x no. trials

Question 15

formula for probability

Answer 15

P(x) = no. times happens x no. trials

Question 16

Perimeter of square

Answer 16

4b

Question 17

Perimeter of react.

Answer 17

2( L + b )

Question 18

Perimeter of circle (circumference)

Answer 18

πd

Question 19

Perimeter of circle arc (circumference)

Answer 19

angle/ 360 x πd

Question 20

Area of square

Answer 20

b^2

Question 21

Area of react

Answer 21

Lb

Question 22

Area of triangle

Answer 22

1/2 x bh

Question 23

Area of trap.

Answer 23

h( a+b )/ 2
a & b are parrel sides
h = hieght btw a & b

Question 24

Area of circle

Answer 24

πr^2

Question 25

Area of rhombus

Answer 25

Lb

Question 26

Area of parallelogram

Answer 26

Lb

Question 27

Area of circle sector

Answer 27

angle/ 360 x πr^2

Question 28

Area of curved surface area of cone

Answer 28

πrL
L = length from bottom to tip

Question 29

Area of surface of Sphere

Answer 29

4πr^2

Question 30

Volume of cube

Answer 30

b^3

Question 31

Volume of cuboid

Answer 31

Lbh

Question 32

Volume of prism

Answer 32

1/2 x bh x h
(cross-section x h)

Question 32

Volume of cylinder

Answer 32

πr^2 h

Question 33

volume of pyramid

Answer 33

1/3 x base area x perpendicular height

Question 34

Volume of cone

Answer 34

1/3 x πr^2 h

Question 35

Volume of Sphere

Answer 35

4/3 x πr^3

Question 36

How to find no. in set

Answer 36

make a equation with total

Question 37

how to do set builder notation?

Answer 37

• ” (set letter) = {x: x ____} “
• x = all values in set
• : = such that
• ______ = add the rule

Question 38

Formula for straight lines

Answer 38

• y = mx + c
  -m = gradient
  -c = y-intercept
  -y & x = not fixed values

Question 39

formula for gradient of straight line

Answer 39

-rise/ run
-without graph: need 2 points
y2 - y1/ x2 - x1
-always make fraction

Question 40

formula for y-intercept of straight line

Answer 40

-need 1 point & gradient
y - y1 = m (x - x1)

Question 41

How to find equation of parallel straight line

Answer 41

-m is same
-change c only

Question 42

how to find gradient of perpendicular straight line (has to intersect at 90)

Answer 42

-m for perpendicular is inverse
- flip fraction & make ( - )

Question 43

formula for midpoint of straight line

Answer 43

• x1 + x2/ 2 (for x)
• y1 + y2/ 2 (for y)
• (x, y)

Question 44

formula for length of straight line

Answer 44

-use Pythagoras
-√ (x2 - x1)^2 + (y2 - y1)^2

Question 45

What is DOPS

Answer 45

-diff of perfect squares
- a^2 - b^2 = (a + b)(a - b)
-eg. x^2 - 9 = (x + 3)(x - 3)

Question 46

Cheats method for linear equations

Answer 46

-only use if no no. before letter
- x^2 _ (no.s [ + ] [letter]) _ (no.s [x])
-eg. (x - 2)^2 = (x - 2)(x - 2)
= x^2 - 4x + 4

Question 47

formula for Pythagoras

Answer 47

-a^2 + b^2 = c^2
-only in right angel

Question 48

formula for median

Answer 48

-nth = no. data
-nth + 1/2 = term

Question 49

formula to find middle of class interval

Answer 49

-find middle of class range by adding the 2 no.s & dividing by 2

Question 50

formula for arithmetic sequence

Answer 50

a n = a1 + (n-1 )d
a n = nth term
a1 = first term
d = diff btw terms

Question 51

formula for geometric sequence

Answer 51

a n = a1 x r^n-1
a n = nth term
a1 = first term
r = ratio

Question 52

Formula for straight lines

Answer 52

y = mx + c
-m = gradient
-c = y-intercept
-y & x = not fixed values

Question 53

formula for gradient of straight line

Answer 53

-rise/ run
-without graph: need 2 points
y2 - y1/ x2 - x1
-always make fraction

Question 54

formula for y-intercept of straight line

Answer 54

-need 1 point & gradient
y - y1 = m (x - x1)

Question 55

formula for length of straight line

Answer 55

-use Pythagoras
-√ (x2 - x1)^2 + (y2 - y1)^2

Question 55

how to find gradient of perpendicular straight line (has to intersect at 90)

Answer 55

-m for perpendicular is inverse
- flip fraction & make ( - )

Question 56

How to find equation of parallel straight line

Answer 56

-m is same
-change c only

Question 57

formula for midpoint of straight line

Answer 57

x1 + x2/ 2 (for x)
y1 + y2/ 2 (for y)
(x, y)

Question 58

congruency tests

Answer 58

(S = side, A = angle)
-SAS
-ASA
-SSS
-AAA
-RHS = Right angle, hypotenuse, S

Question 59

formula for frequency density

Answer 59

frequency/ class width
frequency = diff btw a & b