Similar Figures

Topics for Today:

We used our understanding today in the context of Geometry.  We discussed similar polygons, and know now that similar polygons have the same shape but a different size.  Furthermore, similar polygons have sides that are in proportion to each other.  

Vocabulary:

polygon, similar polygons

Sections Covered in Textbook:

5-6: Using Similar Figures (pages 267-274)

Resources & Tutorials:

1) What are similar figures?

2) How do you find missing measurements of similar figures using a proportion?

3) Using Similar Figures Class notes

Percent of Change

Topics for Today:

We continued the topic of percents in the context of percent of change. We can have a positive percent of change (representing an increase) or a negative rate of change (representing a decrease). To determine the percent of change, we have to compare how much something changed to its original quantity. Percent of change is relative to the original value.

Vocabulary:

percent of change, percent of increase, percent of decrease

Sections Covered in Textbook:

6-8: Finding Percent of Change (pages 327-332)

Resources & Tutorials:

1) What is the percent of change?
2) How do you find percent of change?
3) How do you determine percent of increase or decrease?
4) Percent of Change Class notes

Proportions and Percent Equations

Topics for Today:

We expanded our discussion of proportions to include the percent proportion. We deconstructed the word per-cent to mean "out of 100". We can solve percent problems using a proportion or using a percent equation with the percent expressed as a decimal.

This unit will continue to explore proportions and percents, and we'll take some time to review the conversions of fractions to decimals to percents and vice-versa. Students will be encouraged to memorize the decimal equivalents of common fractions as a time-saver. Normally I am not a big fan of memorization, unless it serves a useful purpose - memorizing common concepts (like divisibility rules, the quadratic formula, and common numbers) can be a big time-saver leaving more time for higher order problem solving.

Vocabulary:

percent, percent proportion

Sections Covered in Textbook:

6-5: Solving Percent Problems Using Proportions (pages 311-317)

Resources & Tutorials:

1) What is a percent proportion?
2) How do you use a proportion to find a whole?
3) How do you use a proportion to find what percent a part is of a whole?
4) How do you use a proportion to find part of a whole?

5) Proportions and Percent Equations Class notes

Solving Proportions

Topics for Today:

We began our unit on solving and applying proportions today, and introduced/reviewed some important vocabulary, beginning with ratios. A ratio is just a comparison of numbers by division. Students have seen ratios ever since they began working with fractions.

We also used the means-extremes (cross products) property to solve proportions.

Vocabulary:

proportion, cross products

Sections Covered in Textbook:

5-5: Using Proportional Reasoning (pages 260-265)

Resources & Tutorials:

1) What is a proportion?
2) How to solve a proportion by using cross products?
3) Solving Proportions Class notes