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Pre-Algebra Notes
Alexis' Pre-Algebra- Angles, Unit Price, Tax, Interest, PEMDAS, 6 types of #s
Term | Meaning |
---|---|
GEOMETRIC RELATIONS... | ******************************************************************** ******************************************************************** |
an angle | rhw measure of the space between 2 rays that meet. Angles are measured in degreese. |
an acute angle | measured less than 90°. |
a right angle | measures exactly 90°. We use a box to show the right angle in it. |
an obtuse angle | measures more than 90° but less than 180°. |
a straight angle | meansures 180° or exactly a half circle. |
a reflex angle | measures more than 180° but less than 360° (1/2 - full circle). |
Rays | sides of the angels. |
Vertex | the meeting point of the rays. |
Complementary angels | 2 angels whose measures add up to 90°. |
Supplementary angels | 2 angels whose measures add up to 180°. |
Adjacent angels | 2 angels that share a ray. |
Linear Pair | 2 angels that are suplementary AND adjacent. |
Vertical angels | Angles opposite of one another when 2 lines intercect. They are congruent. |
Congruent | Having the same shape and size. |
*SHAPES...* | ******************************************************************** ******************************************************************** |
Obtuse triangle | A triangle with 1 obtuse angle. |
Equilateral triangle | Has 3 congruent sides. |
Isosceles triangle | has 2 equal sides |
*SIDES OF A RIGHT TRIANGLE...* | ******************************************************************** ******************************************************************** |
Legs | Sides that make up the right angle. |
Hypotenuse | The side across from the right angle. *Always the longest side of a right triangle. |
*(something important...* | ******************************************************************** ******************************************************************** |
Ratio | A comparison between two values. (ex: with 3 boys and 9 girls: 1:3) |
Proportion | (blank) |
Unit Price | (blank) |
Percent | (blank) |
*SALESTAX...* | ******************************************************************** ******************************************************************** |
What is it? | Money you pay on an item you purchase (sales tax rate: % of tax). |
Where does it go? | Stave gov: roads, schools. |
What is taxed? | Prepared food (restaurant), CDs, DVDs, candy. |
What is NOT taxed? | Food, clothing. |
Tax Formula | tax amount/ticket price= tax rate/100 |
Interest | Money charged/paid for the use of money. |
Principal | Original ammount borrowed/deposited. |
Rate | Percent of the interest (writen as a decimal). |
Time | Amount in time (in years) that the money is borrowed/saved. |
*INTEREST...* | ******************************************************************** ******************************************************************** |
Interest | Money charged/paid for the use of money. |
Principal | Original ammount borrowed/deposited. |
Rate | Percent of the interest (writen as a decimal). |
Time | Amount in time (in years) that the money is borrowed/saved. |
Formula | I=p•r•t |
*PEMDAS...* | ******************************************************************** (order to solve a problem based on the sings.) |
P | Parenthesis |
E | Exponentials (power of #) |
MD | Multiplication/Division |
AS | Addition/Subtraction |
Numonic way to remember: | Please Excuse My Dear Aunt Sally |
*NUMBERS...* | ******************************************************************** ******************************************************************** |
Natural numbers | Counting numbers seen in nature. (N) |
Whole numbers | Natural numbers + 0 (that's it!). (W) |
Intergers | Whole numbers plus their opposites. (Z) |
Rational numbers | All combinations of fractions (positive & negative). (Q) |
Irrational numbers | Any non terminating, non repeating decimal. (O with line on top) |
Real numbers | Every single number. |
*TERMS...* | ******************************************************************** ******************************************************************** |
Term | Number, variable, or product of numbers and variables (terms |
Numerical Term | A term with only numbers |
Variable Term | A term with at least one variable (ex: 5x, -2x, 3xy, xy) |
Combining Like Terms | Focus on the coefficients (the number in the terms). Follow the interger rules to combine them. 2) Then just add them. |
(continued...) | An expression is simplified when all its like terms are combined, and there are no parenthesis left. |