Quantitative Reasoning Flashcards
How do you multiply fractions
Numerators x Numerators
Denominators x Denominators
How do you divide fractions
Flip the second Fraction
Then multiply
How do you add/subtract Fractions
get a common denominator and add/subtract the numerators (don’t change the denominator)
How do you go about comparing Fractions
get a common denominator and compare
How do you set up a ratio
of = on top to = on bottom
how do you solve a proportion
Cross multiply across the = sign
x/5 = 3/4
15/4
How do you do long division
see how many times the deominator can go into the numerator
15/400 = .037
400 goes into .03 times
15.00 - 12.00 = 3
How many times does 400 go into 3 (.007)
change .564 into a fraction
564/1000
282/500
141/250
how do you divide decimals
make them whole numbers and divide
what does percent =
part/whole
How do you find % increase
amount of increase/ Original whole
how do you find probability
of desired outcomes / # of possible outcomes
If we rolled 2 dice, what would be the probability of a total of 4
3 possible desired outcomes / 36 total outcomes (6x6)
how do you multiply powers with the same base
add the exponents
how do you divide powers with the same base
subtract the exponents
how do you raise the power to an exponent
multiply the exponents
how do you multiply powers with the same exponent
multiply the bases keep the exponent
how do you divide powers with the same exponent
divide the bases and keep the exponent
how do you divide polynomials
you just simply do long division with polynomials
What is finding a common factor in a polynomial
when you look at each part of the polynomial is there a common factor between all parts of the polynomial
How do you recognize differences of squares
when you have two identifiable squares with a minus sign between them
4x^2 - 9
(2x-3)(2x+3)
Learn to recognize squares of binomials
a^2 + 2ab + b^2 = (a+2)^2
a^2 - 2ab + b^2 = (a-b)^2
How can you factor out harder polynomials
plug in a 0 and see which answer equals the question. Then check all others to see if there are more. if there are more then plug in another number.
What are two ways to get an unknown out of a denominator
- multiply both sides by the unknown (if alone)
2. get one fraction on each side and cross multiply
how do get the unknown out of an exponent
You must get the bases to equal eachother. you do this by finding what they are both powers of (a common unpower)
8^x = 16 ^ (x-1)
both are unpowers of 2 (2^3 = 8) (2^4 = 16)
(2^3)^x = (2^4)^(x-1)
2^3x = 2^(4x-4)
since the bases are equal you can just set the exponents equal to each other and solve for x
How can you solve quadratic equations
1) get x^2 + x + # = 0 and try to factor the left side
2) quadratic formula
(negative b plus or minus the square root of b squared minus 4 a c. all over 2a)
How do you solve “in terms of” equations
get your variable all alone
What do you do here ax-x = something
divide by a-1
what do you do for aboslut values
think of it as two equations
What to remember when solving for an inequality
if you multiply or divide by a negative number you must flip the sign
When you have (absolute value) < X
or (absolute value) > X
you leave the sign the same
- X < (absolute value) < X
- X > (absolute value) > X
how do you find the area of a triangle
1/2 (base)(Height)
What is the triangle inequality theorum
the length of the third side is smaller than the two other sides added together, but larger than the larger side minus the smaller one
what does the sum of the interior angles of a triangle =
180
what does the sum of the exterior angles of a triangle =
360 (a polygons)
What to remember about similar triangles
- Figure out if they are indeed similar
- If so they have the same angles, and their sides are proportional
- The area of the triangles go as follows
- proportional side ratio 2:1 area equals x^2
- proportional side ratio 3:1 area equals 3^2
(what ever the ratio is, that is raised to the power of two for area)
Isosceles triangle
when two sides, and two base angles are the same
How do you find the area of an equilateral triangle
S^2(Square root of 3)/4
What are some pythagorean triplets
3,4,5 5,12,13 7,24,25 8,15,17 9,40,41 11,60,61
What is the ratio of sides in a 45,45,90 triangle
1: 1:1(Square root of 2)
2: 2:2(square root of 2)
What is the ratio of sides in a 30,60,90 triangle
1:(Square root of 3):2
2:2(square root of 3):2
Hypoteneuse is twice the size of the shortest leg, and the other leg is the short leg times by the square root of three
What is the area of a trapezoid
(Base1 + base2)/2 *height
The bases are the two parallel sides
What is the area of a parallelagram
base * height