Formulas Flashcards
Distance/Work
D/W = RT
Slope
(y2 - y1) ÷ (x2 - x1)
Probability
= #success ÷ #possible
Arc of a circle
arc = portion of the circumference
arc = 2πr * x/360
Sector of a circle
Sector = part of the area extending from the center
sector = πr^2 * x/360
Inscribed angle of a circle properties
- Inscribed angle = half the central arc
- Inscribed angles drawn to same arc have the same measures
- Inscribed angles of equal arc length have equal measures
Volume of a rectangular solid
v = l * w * h
Surface area of a rectangular solid
sum of the area of its faces:
2(lw + wh + hl)
Volume of a cylinder
πr^2h
Surface area of a cylinder
Area of the rectangular band and the two circles
2πrh + 2(πr^2)
Line equation
y = mx + b
m = slope b = y intercept
Percent change
[(difference of original-new) ÷ original]*100
OR
original*(1±change) = final
What percent is A of B?
(“is/was B” ÷ “of A”)*100
Quantity mixutres
When adding values and quantities of two distinct sets/groups
(ratequantity)+(ratequantity) = total cost
Converting units
- determine conversion factor (i.e. 1 year = 35 weeks)
- Multiply original value by conversion factor - put same units on opposite sides of fraction bar:
- ->65 weeks/yr * 1yr/52 weeks
- -> 65/52
- –> 1.25 years
“AND” Probability questions
Questions with 2+ events that happen sequentially - multiply individual probabilities
“OR” Probability questions
Questions asking about the probability of one event OR another - add the probabilities of the individual events
Weighted average
](weight1value1) + (weight2value2)] ÷ sum of weights
Combination problems
Asks for the number of ways in which one or more smaller group/s of elements can be selected from a larger group
—> ORDER DOES NOT MATTER
n! ÷ (s! * k!)
n! = factorial of total group s! = factorial of selected group k! = factorial of unselected group
Permutation problems
Asks you to determine the number of ways in which a smaller group of elements can be arranged from a larger group
Slotting or
n! ÷ s!
Simple interest
Based only on initial deposit
V = P[1*(rt ÷ 100)]
V = value of investment at the end P = principal investment r = interest rate t = time
Compound interest
Interest added to the principal investment at regular time intervals.
V = P[1*(r ÷ 100)^t]
V = value of investment at the end P = principal investment r = interest rate t = time
Average speed
total distance ÷ total time
