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OAT Vocabulary
Kemper 8th grade Vocab
| Question | Answer |
|---|---|
| Mean | Average of a set of Data. Add all the numbers up and divide by the amount of numbers. |
| Mode | The number that appears MOST often. |
| Median | The number in the MIDDLE of a set when the set is in numerical order. If there are 2 middle numbers add the 2 and divide by 2. |
| Range | The DIFFERNCE (subtract) between the biggest and smallest number |
| Perimeter | The distance around an object. (ADD up all of the sides.)Label units. |
| Area | The measure of the region INSIDE a two dimensional object. Label units squared (2) |
| Surface Area | The measure of all faces in a three dimensional object. Label units squared (2) |
| Volume | The amount of space inside a three dimensional object. Label units cubed (3) |
| Area of a square/rectangle | Length times Width. |
| Area of a triangle. | 1/2 bh or bh/2 |
| Area of a cirlce | pi time radius squared (Πr2) |
| Volume of a cube/rectangle prism. | V = BH (B=area of the base) or just do L*W*H |
| Volume of a cylinder. | V = BH which is Πr2h (2 = squared) |
| Volume of a Triangular Prism | V = BH which is 1/2bh(H) H = height of rectangle |
| Volume of a Cone | V = 1/3BH which is 1/3Πr2h (2 = squared) |
| Volume of a Pyramid | V = 1/3BH Depends on the base! |
| Volume of a Sphere | V = 4/3Πr3 (3 = cubed) |
| Surface Area of a Cube | SA = S * S * 6 |
| Sufrace Area of a Rectangular Prism | SA = L*W*2 + L*H*2 + W*H*2 |
| Surface Area of a Triangluar Prism | SA = 1/2bh*2 (triangles) + L*W (for all 3 rectangles - do each rectangle by itself) |
| Surface Area of a Square Pyramid | SA = L*W (base) + 1/2bh4 (faces) |
| Surface Area of a Cylinder | SA = 2Πr2 + 2Πrh |
| Order of Operations | PEMDAS "Please Excuse My Dear Aunt Sally)Parenthesis, Exponents, (Multiplication or Division - Left to right), (Addition or Subtraction - left to right) |
| Square Root | A number that when multiplied by itself gives a given number. Ex: Square root of 9 is 3 (3x3=9) |
| How to Solve Equations | UNDO the Order of operations. |
| Like terms | Terms that have the same variable to the same exponent. Ex; 3x + 12x is the same as 15x. But 3x + 15y can't be combined |
| Distributive Property | Take the value outside the parenthesis and multiply it by EVERYTHING on the inside. |
| Proportion | An equation with 2 ratios. Cross multiply to solve. |
| Percent Proportion | IS/OF = %/100 Cross multiply to solve. |
| Natural Numbers | 1,2,3,.... The numbers we COUNT by. |
| Whole Numbers | 0,1,2,3... Natural number and 0 |
| Integers | Whole numbers and there opposites. ... -2,-1,0,1,2,3... |
| Rational numbers | They EITHER STOP (2, .635, .1, 100) or REPEAT (1/3 = .333333...)Every fraction goes here. |
| Irrational numbers | Never stop or repeat Ex: pi |
| Scientific Notation | A method of writing or displaying numbers in terms of a decimal number between 1 and 10 multiplied by a power of 10. The scientific notation of 10,492, for example, is 1.0492 × 10^4 positive exponent = bigger than 1, negative exponent = smaller than one |
| Fraction to Decimal | Divide numerator (top) by denominator (bottom)EX: 2/5 = 2 divded by 5 = .4 |
| Fraction to Percent | Divide numerator by denominator and multiply by 100 or just move the decimal 2 places right. 2/5 = .4 = 40% |
| Percent to Decimal | Move decimal two places left. EX 5% is .05 |
| Percent to Fraction | Put the Percent over 100 and reduce. Ex: 50% = 50/100 = 1/2 |
| Decimal to Percent | Move decimal two places right. Ex: .045 = 4.5% |
| Decimal to fraction | Move the decimal the amount of spaces needed to make it a whole number (no decimal) and put it over a 1 with as many zeroes as you moved spaces. Ex: .24 (move 2 places) 24/100 = 6/25 |
| Substitution | Taking a value and plugging it in for a variable. |
| Variable | A letter/symbol that takes the place of a number. |
| How to find an Interior Angle | 3 sided figures = 180 degrees, 4 sided figures = 360. Just add 180 degress for each side above this and then subtract the angles you have from the total. |
| Unit rate | A ratio with the denominator being 1. Ex: 10 apples cost $2.00 so 10/2.00 reduces to 1 apple/.20 cents. |
| Sales Tax | The amount of money ADDED to the total. Ex: 6% tax on $50.06 * 50 = 3 Tax is 3 dollars. Add 3 to 50 to get a total of $53 |
| Discount | The amount of money SUBTRACTED from the price/cost. Always done before tax.Ex: 6% tax on $50.06 * 50 = 3 Discount is 3 dollars. Subtract 3 from 50 to get a total of $47 |
| Coordinate Plane | Coordinate Plane is a plane formed by the intersection of a horizontal number line with a vertical number line. |
| Origin | Where the x-axis and y-axis intersect (0,0) |
| Coordinate Point | A point on the graph (X,Y) +X move right, -X move left. +Y move up, -Y move down. |
| X-Axis | The horizontal line (left-right) |
| Y-Axis | The vertical line (up-down) |
| Quadrants | The 4 areas on the graph, labeled with roman numberals I is in the top right and you move counter clockwise. |
| Slope | The steepness of a line. Rise over Run. Count from one point to another. Go up first(positive), and then Right (positive)or Left(Negative) reduce fraction. |
| Slope Formula | y-y/x-x Take the y-value from on point and subtract the other. Then take the x-value from the first point you used and subtract the other x. Then reduce your fraction. |
| Slope Intercept Form | Y=mx+b m=slope, b= y-interceptPlot y-intercpt first and then use slope to get the second point. |
| Parallel lines | Have the same slope. |
| Perpendicular Lines | Have opposite reciprocal slopes. Ex; 1/4 and -4/1 |
| Translation | To SLIDE a figure. ADD the x to the x points and y to the y points. |
| Reflection | To FLIP over an axis. If you reflect over the x-axis you keep the x value and change the y to the opposite. If you flip over the y-axis you keep the y-value and change the x to the opposite sign. |
| Rotation | To Rotate an object around the origin. 90 degree counterclockwise - flip the x and y and change the sign of the new x180 degree rotation - change the sign of x and y. |
| Dilation | To enlarge or reduce the size of an object. Multiply the dilation by the x and y to get the new points. |
| Similar Figures | Same shape but different size. |
| Congruent Figures | Same shape and size. |
| Theoretical Probability | What the outcome should be based on the odds.Ex: If you flip a coin 10 times, how many heads should you get? 5/10 |
| Experimental Probability | What you acutally get after doing the experiment. |
| Pythagorean Theorem | A squared + B squared = C squaredA,B are legs and C is the hypotenuse |
| Hypotenuse | Side opposite the right angle; longest side of a right triangle. |
| Arithmetic Sequence | Common difference between terms (Add/subtract same number) Ex. 2,4,6,8... (+ 2) |
| Geometric Sequence | Common ratio between terms (multiply same number)Ex. 16, 4, 1, 1/4.... (X by 1/4) |
| Ratio | Comparison Between two or more things. Write as a fraction. |