math formulas Flashcards
Simple Interest rate
Interest= (principle)(rate)(time)
Principle is the amount of money initially invested or deposited
rate is annual interest rate
time is the time the money stays there
Percent Increase Change
% change= change × 100 / original change
Area of a Sector
X/360 times (πr²)
Length of an arch
Pythagorean triple
**3:4:5 **
5:12:13
8:15:17
7:24:25
90,45,45 triangle
90,60,30 Triangle
Compound Interest
P = Principal
r = annual interest rate (as a decimal
c = number of “compoundings” per year
n = number of years
sum of angels
180°(n-2)
Given two sides of length a and b in a triangle
difference of a and b ∠ length of third side ∠ sum of a and b
A-B < C < A+B
time
distance/rate
Area of a Rhombus
Avg. speed
Distance between two points
Distance
Rate x Time
Time
distance / rate
Slope
Combination Formula
n being the number of items
r being the number of groups or combo// or objects that can be selected from n
arranging objects when they are alike
(Mississippi Rule)
for instance Nanny
Range
Max - Min
Finding a certain sequence
Xn=3n+2
n being the value of the term in the order
For instance:
if n>0
we give n=1 to find the first term
Permutation formula
Percentages: % Decrease
(Amount of Decrease/ Original Whole) x 100%
Percentages: % Increase
(Amount of Increase/ Original whole ) x 100%
Percentages: New Whole
New Whole = Original Whole + or - Amount of Change
The total number of primes from 1-100
25
Sum of integers
Converting fractions into decimals
11²
121
12²
144
13²
169
14²
196
15²
225
16²
256
1/5
20%
0.2
Fact about Remainder
possible values of remainder
N and D are positive intergers. When N is divided by D the remainder is R. What are some possible values of N?
N ÷ D = Q(R)
Possible values of N:
R
R + D
R + 2D
R + 3D
….
Surface area of a cylinder
One feet is…
12 Inch
Direct Variation
as X increases Y increases
2 bananas/ 1 $ = 5 bananas/ X
Inverse variation
as x increases y decreases
(3 men) (2 hours) = (5 men)(x hours)
Quadratic Formula
If (b²- 4ac) < 0 ==> then there is no solutions
Probablity formula with OR
Probabiltiy with AND
Probability at least
Problem:
on fair dice is rolled 8 times. What is the probability of rolling at least one six?
Greatest common factor of
x
Facts about radicals
