click below
click below
Normal Size Small Size show me how
math for ACT
Question | Answer |
---|---|
IMAGINARY NUMBERS | NUMBERS THAT INVOLVE SQUARE ROOTS OF NEGATIVE NUMBERS |
EVEN NUMBER ARE DIVISIBLE BY | 2 |
prime numbers are divisible by | 1 and itself |
composite number | divisible by more than just 1 and itself eg..4,6,8,9,10,12,14,15... |
squared means | numbers are multiplied by themselves. eg..2x2=4 3x3=9 1,4,9,16,25,36... |
cubed means | numbers are multiplied by themselves twice 2x2x=8 3x3x3=27 |
triangle formulas | perimeter=side+side+side area=1/2bh |
square formulas | perimeter=4s area=sxs or s2 |
rectangle formulas | perimeter=2(b+h),or 2b+2h Area=bh or lw |
parallelogram formulas | perimeter = 2(l+w), or 2l +2w Area =bh |
Trapezoid formulas | perimeter = b1 + b2 + s1 + s2 Area = 1/2h(b1 + b2) or h(b1 + b2) -------- 2 |
circle formulas | circumference = 2pieR or pieD area = pieR2 |
cube formulas | Volume = s~s~s=s3 Surface area = s~s~6 |
rectangular prism | Volume = l~w~h Surface area = 2(lw) + 2(lh) +(wh) |
1/100 | .01 1% |
1/10 | .1 10% |
1/5 = 2/10 | .2 .20 20% |
3/10 | .3 .30 30% |
2/5 = 4/10 | .4 .40 40% |
1/2 = 5/10 = | .5 .50 50% |
3/5 = 6/10 = | .6 .60 60% |
7/10 = | .7 .70 70% |
4/5 = 8/10 = | .8 .80 80% |
9/10 = | .9 .90 90% |
1/4 = 25/100 = | .25 25% |
3/4 75/100 = | .75 75% |
1/3 = | .33 1/3 = 33 1/3% |
2/3 = | .66 2/3 = 66 2/3% |
1/8 = | .125 .12 1/2 = 12 1/2% |
3/8 = | .375 = .37 1/2 = 37 1/2% |
5/8 = | .625 = .62 1/2 = 62 1/2% |
7/8 = | .875 = .87 1/2 = 87 1/2% |
1/6 = | .16 2/3 = 16 2/3% |
5/6 = | .83 1/3 = 83 1/3% |
1 = | 1.00 = 100% |
2 = | 2.00 = 200% |
3 1/2 = | 3.5 = 3.50 = 350% |
3ft = | yard |
36 inches = | 1 yard |
1760 yards = | 1 mile |
5280 ft = | 1 mile |
5 1/2 yards = | 1 rod |
144 sq in = | 1 sq ft |
16 oz = | 1 lb |
2000 lbs = | 1 ton |
8 ounces | 1 cup |
2 cups | 1 pint |
2 pints | 1 quart |
4 quarts | 1 gallon |
8 dry quarts | 1 peck |
4 pecks | 1 bushel |
10 yrs | 1 decade |
100 yrs | 1 century |
kilometer = | 1000 meters |
hectometer (hm) | 100 meters |
dekameter(dam) | 10 meters |
10 decimeters | 1 meter |
1000 millimeters(mm) | 1 meter |
1000 milliliters | 1 liter |
1000 liters | 1 kiloliter (kl) |
terms of division | quotient divisor dividend ratio parts |
vertical angles | formed by two intersecting lines,across from each other,always equal |
adjacent angles | next to each other, share a common side and vertex |
right angle | 90 degrees |
straight angle, or line | measures 180 degrees |
angle bisector | divides an angle into two equal angles |
supplementary angles | two angles whose total is 180 degrees |
complementary angles | two angles whose total is 90 degrees |
what determines a line | two points |
parallel lines | never meet; slopes are the same |
perpendicular lines | meet at right angles; slopes are opposite reciprocals(ex: 1/3 and -3) |
polygon | many sided (more that two) closed figure |
regular polygon | a polygon with all sides and all angles equal |
triangle | three sided polygon; interior is 180 degrees |
equilateral | all sides are equal |
isosceles triangle | two sides are equal |
scalene triangle | all sides are different |
in a triangle- | angles opposite equal sides are equal |
in a triangle - an exterior angle | is equal to the sum of the remote two angles |
median of a triangle | a line segment that connects the vertex and the midpoint of the opposite side |
quadrilateral | four-sided polygon interior angles total 360 degrees |
parallelogram | a quadrilateral with opposite sides parallel |
rhombus | a parallelogram with equal sides |
trapezoid | a quadrilateral with two parallel sides |
pentagon | five sided polygon |
hexagon | SIX sided polygon |
radius of a circle | a line segment from the center of the circle to the circle itself |
diameter of a circle | a line segment that starts and ends on the circle and goes through the center |
chord | a line segment that starts and ends on the circle |
arc | a part of the circle |
to reduce a fraction | find the common denominator |
to multiply fractions | line them up and multiply straight across |
to divide fractions | invert the second and multiply |
to change a fraction to a decimal | divide denominator into numerator |
order of operation | p.e.m.a.s |
every fraction implies | another fraction |
a decimal is just another way to | express a fraction |
in an average question you should think | total divided by #of things times average |
3x + 7 = 28 first step is | do the opposite of addition and subtract 7 |
3x + 7 = 28 the second step | 3x = 28 get rid of the 3 do the opposite and divide both x=7 |
Act English, is (any form of the word be) IS THE SAME AS | = |
Act English, of product times | x(multiply) |
Act English, what a certain number | x,y,z(your favorite variable |
Act English, what percent | x/100 |
Act English,more than, is added to the sum of increased by | add |
one equation and two variables | can not be solved |
working backwards on math questions | is often easier |
when you solve an inequality, remember if you multiply or divide by a negative number | the sign flips |
degrees in a circle | 360 |
degrees in a quadrilateral | 360 |
degrees in a line | 180 |
degrees in a perpendicular angle | 90 |
degrees in a triangle | 180 |
in geometry, because the problems are always drawn to scale | it will be possible to get very close approximation of the correct answers before you even do the problem |
if you have no diagram | draw one |
Transitive axiom | If a = b and b = c, then a = c. 1+3=4 and 4=2+2 then 1+3=2+2 |
cross multiplying notes | Cross multiplying can be used only when the format is two fractions separated by an equal sign. |
reflexive | noting a relation in which each element is in relation to itself, as the relation “less than or equal to |
axiom (a=a) | a proposition that is assumed without proof for the sake of studying the consequences that follow from it. |
Symmetric axiom | if a=b then b=a |
solving equations | |
cross multiplying in algebra | Be aware that cross multiplying is most effective only when the letter you are solving for is on the bottom of a fraction. |
Addition/Subtraction Method | Combine equations to eliminate one variable. The equations may need to be multiplied by a common multiple first. |
substitution method | Solve one equation for one variable and substitute that variable into other equations. |
grafting method | Graph each equation on the same graph. The coordinates of the intersection are the solution. |
to multiply Monomials | add the exponents of the same bases: x4(x3) = x7. 9882.html#ixzz0knPnlwRf |
to divide monomials | subtract the exponent of the divisor from the exponent of the dividend of the same base: x8/x3 = x5. |
add/subtract equations | Combine equations to eliminate one variable. The equations may need to be multiplied by a common multiple first. |
add/subtract polynomials | add/subtract like terms only |
multiply two polynomials | multiply each term in one polynomial by each term in the other polynomial. |
the f.o.i.l method | first-outer-inner-last is often used when multiply binomial |
binomial | an expression that is a sum or difference of two terms, as 3x + 2y and x2 − 4x. |
To divide a polynomial by a monomial | divide each term by the monomial |
to divide a polynomial by another polynomial | make sure both are in descending order, then use long division (divide by first term, multiply, subtract, bring down). |
distance is | rate x time |
interest is | principal x rate x time |
work accomplished | rate of work x time worked |
How many irrational numbers are between 1 and 6 | there are an infinite number of irrational numbers between any two real numbers. |
A number is divisible by 2 if its last digit is | 0,2,4,6,8 |
A number is divisible by 3 if the sum of its digits is divisible by 3. | 168 is divisible by 3 since the sum of its digits is 15 (1+6+8=15), and 15 is divisible by 3. |
A number is divisible by 4 if the number formed by its last two digits is divisible by 4. | 316 is divisible by 4 since its last two digits are 16 and 16 is divisible by 4. |
A number is divisible by 5 if its last digit is either 0 or 5. | 195 |
A number is divisible by 6 if it is divisible by 2 AND it is divisible by 3. | 168 is divisible by 6 since it is divisible by 2 AND it is divisible by 3. |
A number is divisible by 8 if the number formed by its last three digits is divisible by 8. | 7,120 is divisible by 8 since its last three digits are 120 and 120 is divisible by 8. |
A number is divisible by 9 if the sum of its digits is divisible by 9. | 549 is divisible by 9 since the sum of its digits is 18 (5+4+9=18), and 18 is divisible by 9. |
any number raised to the 0 power is | 1 eg 1490 to the zero power = 1 |
any number raised sto the 1st power is itself | 81 =8 raised to the first power |
a negative sign applied to a group | changes the sign of each term in the group -(a+b)= -a + -b -(a + -b) = -a + b |
Rules for subtracting integers: | # Change the problem to an addition problem. * Subtracting a negative becomes adding a positive. * Subtracting a positive becomes adding a negative. |
Rules for adding integers: | neg+neg=neg pos+pos=pos poa+neg subtract keep the sign of the larger number |
Rules for multiplying integers: | * A positive times a positive equals a positive. * A negative times a negative equals a positive. * A positive times a negative equals a negative. * A negative times a positive equals a negative. |
Rules for dividing integers: | # positive divided by a positive equals a positive. # A negative divided by a negative equals a positive. # A positive divided by a negative equals a negative. # A negative divided by a positive equals a negative. |
To cube a number | raise it to the third power |
a root is | the opposite of an exponent spuare root of 81 is 9..16 is 4 |
order of operations | parentheses-exponents and roots-do all multiplication and division left to right -do what comes first do not do all multi than division do what comes first |