**Notes on set theory and Venn diagrams**

**Notes on rates based on powers of ten, most often on the per 100,000 scale**

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Online notes for Math 15, Math for Liberal Arts taught in the Fall 2016 semester at Laney College by Prof. Hubbard.

## Thursday, October 12, 2017

## Monday, October 9, 2017

## Thursday, September 28, 2017

## Wednesday, September 20, 2017

## Wednesday, September 13, 2017

## Wednesday, September 6, 2017

###
Fractional part of a day

A year is defined by how long it takes a planet to make a single orbit around the sun.**An Earth year is 365.2422 days.** To make up for the decimal part we have a leap year every four years and skip the leap year if the number of the year is divisible by 100. This means we had leap years in 2004, 2008, 2012 and 2016, but we did not have one in 2000. What this lesson is about is to take the decimal part of this time and turn it onto hours, minutes and seconds.

** **

**Step 1. Multiply the decimal part by 24 to get the number of hours. **

In this case, .2422 x 24 = 5.8128, which means 5.8128 hours.

**Step 2. If there is still a decimal part, multiply it by 60 to get the number of minutes.** We know know a year is 365 days, 5 hours and some number of minutes. That number is 60 x .8128 = 48.768

**Step 3. If there is still a decimal part, multiply it by 60 to get the number of seconds.**

We know know a year is 365 days, 5 hours, 48 minutes and some number of seconds. That number is 60 x .768 = 46.08. In these problems, it is okay to round to the nearest tenth of a second, so the final answer is**365 days, 5 hours, 48 minutes and 46.1 seconds.**

Let's do another example. A year on Venus is 224.65 Earth days.

** **

**Step 1.** .65 x 60 = 15.6, so the year on Venus is 224 days, 15.6 hours.

**Step 2. **60 x .6 = 36, so that makes the year on Venus **224 days, 15 hours and 36 minutes.** There is no more decimal part, so we don't have to add any seconds to our answer.

Here are two more practice problems. The answers are in the comments.

1. It takes Mercury 87.969 Earth days to travel around the sun. Write this number in days, hours, minutes and seconds.

2. It takes Mars 686.98 Earth days to travel around the sun. Write this number in days, hours, minutes and seconds.

## Thursday, August 31, 2017

## Wednesday, August 23, 2017

## Monday, August 21, 2017

## Friday, July 21, 2017

## Tuesday, July 18, 2017

###
Notes for Homework 8, duy Wed. July 19

A quick reminder: this homework will not be accepted late because the answer sheet will be given out at the end of class to help study for Thursday's midterm.

**Notes on scientific notation**

**Notes on Set Theory**

**Notes on Venn Diagrams**

**Notes on contingency tables and probabilities**
## Thursday, July 13, 2017

## Tuesday, July 11, 2017

## Thursday, July 6, 2017

## Thursday, June 29, 2017

## Wednesday, June 28, 2017

## Saturday, June 24, 2017

## Tuesday, June 20, 2017

## Monday, June 19, 2017

## Friday, March 24, 2017

## Thursday, March 16, 2017

## Wednesday, March 8, 2017

## Saturday, March 4, 2017

## Sunday, February 19, 2017

###
Notes for Homework 4, due Wed. Feb. 22

Because of the Monday holiday, homework is due on Wednesday. There will be no quiz this week.

**Notes on the Richter scale and bels and decibels, abbreviated B and dB.**

**Notes on square roots and the Pythagorean Theorem.**

## Friday, February 10, 2017

## Thursday, February 2, 2017

## Wednesday, January 25, 2017

## Special posts

## Blog Archive

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A year is defined by how long it takes a planet to make a single orbit around the sun.

In this case, .2422 x 24 = 5.8128, which means 5.8128 hours.

We know know a year is 365 days, 5 hours, 48 minutes and some number of seconds. That number is 60 x .768 = 46.08. In these problems, it is okay to round to the nearest tenth of a second, so the final answer is

Let's do another example. A year on Venus is 224.65 Earth days.

Here are two more practice problems. The answers are in the comments.

1. It takes Mercury 87.969 Earth days to travel around the sun. Write this number in days, hours, minutes and seconds.

2. It takes Mars 686.98 Earth days to travel around the sun. Write this number in days, hours, minutes and seconds.

A quick reminder: this homework will not be accepted late because the answer sheet will be given out at the end of class to help study for Thursday's midterm.

Because of the Monday holiday, homework is due on Wednesday. There will be no quiz this week.

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- 100 coins
- all factors
- angles and sides
- area of a triangle
- binary
- biographies
- bitwise operators
- classification of three vertex triangle
- classification of triangles
- coin problems
- compound interest
- computer science
- conditional probability
- Consumer Price Index
- contingency tables
- corrections
- decibel and bel scale
- decimal
- decimals
- distance
- divisibility
- effective interest rates
- Finding the square root of any number
- five number summary
- Fractional part of a day
- fractions
- geometry
- half life
- Heron's formula
- hexadecimal
- homework answers
- Important class dates Fall 2016
- inclusion-exclusion rule
- interest and loans
- linear equations
- logarithms
- logic
- Math history.
- metric system
- numbers and representation
- old school
- order of operations
- outliers
- overflow
- percents
- Polish notation
- powers of 10
- practice
- practice problems
- prime factorization
- prime numbers
- probability
- probability based on contingency tables
- Pythagorean theorem
- regular polygons
- repeating decimals and fractions
- Richter scale
- Roman numerals
- rounding
- scales based on powers of 10
- scientific notation
- scientific notation notes
- set theory
- significant digits
- simultaneous equations
- slope
- square roots
- statistics
- syllabus
- three dimensional geometry
- tilings of the plane
- time
- triangle inequality
- truth tables.
- underflow
- Venn diagrams
- weights and measures
- z-scores