Category: Geometry

Posted in Algebra, Geometry, Math blogs

Math and Multimedia Carnival #7

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Welcome to the 7th edition of Math and Multimedia blog carnival.

Before we begin Carnival 7, let’s look at some of the trivias about the number seven:

Now, lets start with posts that involve mathematics sans technology.

Guillermo P. Bautista Jr., the organizer of Mathematics and Multimedia Carnival, presents Generating Pythagorean Triples posted at Mathematics and Multimedia, saying, “A simple strategy in generating Pythagorean Triples.”

Mike Dimond presents Squares ending in 5 – Two Digit Numbers posted at Education For All, saying, “Learn how to quickly calculate the square for two digit numbers ending in five. The post goes over how to quickly calculate 75 * 75.”

I also grab the post Numbers and Variables, the first in the series of post on teaching algebra to students in their first year of High School from the blog Learning and Teaching Math.

John Golden presents Math Hombre: Variable and a Problem posted at Math Hombre, saying, “This post tries to give a couple of contexts for middle school or Algebra I development of the concept of variable.”

Let me include on this list my latest post titled  Counting Smileys which shows several solutions to counting problems that are used to introduce variables and algebraic expressions.

click link to view source

Now, for mathematics with technology:

David Wees presents Is Interactivity in Mathematics Important posted at Professional blog | 21st Century Educator, saying, “This blog post is a discussion of the importance of using interactive tools when teaching mathematics.” This is one way indeed to involve students in the learning.

Alexander Bogomolny presents Fascination with Tessellations posted at CTK Insights. The post presents several Java applets that illustrate various hinged tessellations and ways of inserting hinges into an existing tessellation.

Terrance Banks presents Treasure Hunt Activity posted at So I Teach Math and Coach?, saying, “Review Activity – Treasure Hunt for Algebra”

Gianluigi Filippelli presents Gravity vs height posted at Science Backstage, saying, “The dependance of gravity by height plotted with Scilab”

Tamarah Buckley presents Instant Feedback posted at Infinitely Many Solutions, saying, “My blog focuses on using iPads in a secondary math classroom.”

Pat Ballew presents Microsoft Mathematics is FREE! posted at Pat’sBlog, saying, “Software for every kid, at just the right price…”

Finally, let me share my post on Squares and Square Roots which presents a series of activities for teaching these concepts meaningfully using the free software, GeoGebra.

That concludes this edition. Submit your blog article to the next edition of mathematics and multimedia blog carnival using our carnival submission form. Past posts and future hosts can be found on our blog carnival index page

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Posted in Algebra, Geogebra, Geometry, High school mathematics

Teaching with GeoGebra: Squares and Square Roots

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This post outlines a teaching sequence for introducing the concept of square roots in a GeoGebra environment. Of course you can do the same activity using grid papers, ruler and calculator. However, if the students have access to computers then I highly recommend that you use GeoGebra to do this. In my post GeoGebra and Mathematics, I argued that the more the students understand the mathematics behind GeoGebra, the more confident they could become in using this tool. The earlier the exposure to this environment, the better. The way to do this is to integrate the learning of the tool in learning mathematics.

The figure below is the result of the final activity in my proposed teaching sequence for teaching square roots of numbers and some surds or irrational numbers. The GeoGebra tool that the students is expected to learn is the tool for constructing general polygons and regular polygons (the one in the middle of the toolbar).

Squares and Square Roots

The teaching sequence is composed of four activities.

Activity 1 involves exploration of the two polygon tools: polygons and regular polygons. To draw a polygon using the polygon tool is the same as drawing polygons using a ruler. You draw two pints then you use the ruler/straight edge to draw a side. But with Geogebra you click the points to determine the corners of the polygon and Geogebra will draw the lines for you. In the algebra window you will see the length of the segment and the area of the polygon. Click here to explore.

GeoGebra shows further its intelligence and economy of steps in Activity 2 which involves drawing regular polygons. Using the regular polygon tool and then clicking two points in the drawing pad, GeoGebra will ask for the number of sides of the polygon. All the students need to do is to type the number of sides of their choice and presto they will have a regular polygon. Click here to explore.

Activity 3 is the main activity which involves solving the problem Draw a square which is double the area of another square. Click here to take you to the task.

Activity 4 consolidates ideas in Activity 3. Ask the students to click File then New to get a new window from the previous activity’s applet then ask them to draw the figure above – Squares and Square Roots.  You can also use the figure to compare geometrically the values of \sqrt{2} and 2 or  show that \sqrt{8} = 2\sqrt{2}. This activity can be extended to teach addition of radicals.

Like the rest of the activities I post here, the learning of mathematics, in this case the square roots of numbers, is in the context of solving a problem. The activities link number, algebra, geometry and technology. Click here for the sequel of this post.

This is the second in the series of posts about integrating the teaching of GeoGebra and  Mathematics in lower secondary school. The first post was about teaching the point tool and investigating coordinates of points in a Cartesian plane.

GeoGebra book:

Model-Centered Learning: Pathways to Mathematical Understanding Using GeoGebra

Posted in Geometry

Problem Solving Involving Quadrilaterals

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‘To understand mathematics is to make connections.’ This is one of the central ideas in current reforms in mathematics teaching. Every question, every task a teacher prepares in his/her math classes should contribute towards strengthening the connections among concepts. There are many ways of doing this. In this post I will share one of the ways this can be done: Use the same context for different problems.

The following are some of the problems that can be formulated based on quadrilateral BADF.  You can pose these problems to your class but the best way is to simply show the diagram to the students then ask them to formulate the problems themselves.

quadrilateral

Problem #1. What is the area of the quadrilateral? Show different methods.

The solution to this question depends on the grade level of students. The one shown below can be done by a Grade 5 or 6 student. Continue reading “Problem Solving Involving Quadrilaterals” →