SAT cram vocab and formulas

reverse percentage formula

A method used to calculate the original amount before a percentage increase or decrease was applied. It is expressed as: Original Amount = Final Amount / (1 ± Percentage Rate).

how to convert radians to degrees?

multiply radian value by 180/pi

how to convert degrees to radians?

multiply degree value by pi/180

equation of a circle

(x-h)²+(y-k)²=r²

center of a circle

(h,k)

radius of a circle

r

how to get circumference given arc length and central angle?

use the proportion: (arc length)/(circumference)=(central angle)/360

Laconic

using very few words; brief and to the point

Impious

not showing respect or reverence, especially for a god.

Avarice

an intense, insatiable, and often reprehensible desire for wealth and material possessions, frequently described as extreme greed

Supersede

take the place of (a person or thing previously in authority or use); supplant.

Impervious

not allowing fluid to pass through.

Affable

friendly, good-natured, or easy to talk to.

Elucidate

to make something clear, explain in detail, or throw light upon a complex subject

Equivocate

to be ambiguous, not upfront

Calamitous

having extremely unfortunate or dire consequences

Adulation

The largest group to which a study’s result can be generalized to is…

the location from which the survey was taken

(ex. 35 students at a middle school = the middle school)

The area of a sector, angle in degrees

degrees/360 * πr²

The area of a sector, angle in radians

½ * r *degree

The area of a sector, using arc length

1/2rs

equation of a circle

\((x - h)^2 + (y - k)^2 = r^2\)

• (h,k) is the center

• r is the radius

• x and y are coordinates of anywhere on the circle

cylinder surface area

2πrh+2πr²

sphere surface area

4πr²

cone surface area

πr(r+h2+r2)

pyramid surface area

lw + l √(w/2)²+h² +w√(l/2)²+h²