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# Miscellaneous Review

### Circles, Simple Interest, Percent of Change, Probability

Term | Definition |
---|---|

Circumference of a Circle | C = pi * diameter; the distance around the outside of a circle. |

Area of a Circle | A = pi * radius^2; the number of square units that fit inside of a circle |

Radius | the distance from the center to the circumference of a circle; it is half the length of the diamter |

Diameter | a straight line going through the center of a circle connecting two points on the circumference; it is double the length of the radius |

Probability | the chance that something will happen; the ratio of the number of ways an event can occur over the total number of possible outcomes |

Sample Space | a list of all the possible outcomes; each outcome should be written in parentheses with a comma between events. For example (Heads, 6) represents flipping a heads on a coin and then rolling a 6 on a number cube |

Impossible Event | never going to happen; probability = 0 or 0% |

Certain Event | definitely going to happen; probability = 1/1 or 1.0 or 100% |

Independent Events | the outcome of one event DOES NOT affect the probability of the other event; example: rolling a number cube and then flipping a coin |

Dependent Events | the outcome of one event DOES affect the probability of the other event; example: picking a jelly bean from a jar, eating it, and then picking a second |

Theoretical Probability | what you expect to happen |

Experimental Probability | what actually happens |

Simulation | an experiment designed to model the action in a given situation. For example, flipping a coin could be used as a simulation for having a boy or girl baby. |

Suppose you flip a coin and then roll a die. Find P(H, even #) | 1/2 x 3/6 = 3/12 or 1/4 |

A bag of marbles contains 3 red, 5 blue, and 2 green marbles. Suppose you choose a marble, don't replace it, and then choose another. Find P(blue, blue) | 5/10 x 4/9 = 20/90 or 2/9 |

Unlikely Event | Probability is greater than 0 but less than 1/2 (50%) |

Likely Event | Probability is greater than 1/2 (50%) but less than 1 (100%) |

Simple Interest Formula | I = prt; I = interest, p = principal (total $ invested or borrowed), r = rate (percent, but written in decimal form), t = time (in years) |

Percent of Change Proportion | change/original = %/100 |

If the area of a circle = 100pi, find the radius and diameter. | radius = 10; diameter = 20 |

If the circumference of a circle = 12pi, find the radius and diameter. | radius = 6; diameter = 12 |