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Posts Tagged ‘ratios’

Similar Triangles

Tuesday, September 15th, 2009

Introduction to Similar Triangles

Description

A detailed tutorial on the introduction to similar triangles. Step by step tutorial including several examples of how to solve similar triangles for reference.

Overview

Similar triangles are triangles that have the exact same angles, although the lengths of the sides may be different. This is what makes them similar, and not equal. However, the sides do correspond. Corresponding sides are sides that are opposite the same angle – meaning angles that have the same measure. Something that can help you find out the missing lengths of a similar triangle is that the ratios are always the same. As long as you have all the lengths of the sides of the other triangle, you will always be able to find the missing lengths.

Tags: angles, corresponding, corresponding sides, Geometry, lengths, Math, ratios, similar, similar triangles, triangle
Posted in Geometry | No Comments »

Cross Multiplication

Thursday, September 3rd, 2009

How to Solve Problems Using Cross Multiplication

Description

This video gives an example of how to solve proportions using the cross-multiplication technique. Several examples are provided as well as easy to follow step-by-step instructions. This video also provides sample word problems, with examples of how to use the cross-multiplication technique with word problems.

Overview

Cross multiplication is often used with fractions and proportions, and is found in many word problems. A cross multiplication problem will normally have two fractions set equal to each other, with one fraction complete, and one fraction with one variable in either the numerator or the denominator. Take the numerator of the first fraction and multiply it by the denominator, then set it equal to the denominator of the first fraction multiplied by the numerator of the second fraction. An example is x / y = a / b. You would change this to x * b = y * a. From there you can simply solve for the variable.

Tags: algebra, cross multiplication, fractions, Math, proportions, ratios, word problems
Posted in Algebra | No Comments »

Ratios & Proportions

Thursday, September 3rd, 2009

How to Write and Solve Ratios & Proportions

Description

This video gives an introduction to ratios and proportions. Included are several examples of each, and a quick tutorial on how to make more ratios from one ratio that you are given, which will create a proportion.

Overview

Ratios, while used in basic math, is most commonly used in statistics. The number of something to the number of something else is used very often to illustrate the different between something. There are three different notations for this – X to Y, X:Y, and X/Y. They all mean the same thing and are all in the same order. Proportions can be thought of as two ratios measuring the same thing. Sometimes, one of these will have a variable, an unknown quantity. Proportions like this can be solved using cross multiplication, and can often be found in word problems.

Tags: algebra, cross multiplication, fractions, Math, proportions, ratios, word problems
Posted in Algebra | No Comments »