Rubber Bands and Picks

On Wednesday we went over the concepts of measurement and area. We did an activity sheet that showed pictures of pins and lines forming geometric patterns. We had to count the number of squares and outer pins that formed the geometric shapes. We used the number of squares to find the area and the number of outer pins to find the perimeter of the geometric shapes. We also did a classroom activity involving rubber bands and pins. By stretching around the rubber bands we were able to form geometric shapes. We then applied the same method from the activity sheet to count the number of squares and outer pins. We also went over the concept of Pick’s Theorem.

Pick’s Theorem is A = 1/2 x P – 1

Example:

If a geometric figure has a perimeter of 8 pins, what is the area of the geometric figure?

A = ½ x 8 + 2 – 1

A = (1/2 x 8) + 2 – 1

A = 4 + 2 – 1

A = 6 – 1

A = 5

The area is 5 or I have 5 squares in the geometric figure.

Another method is A = ½ P + I – 1

The I stand for the interior pins that are inside of the geometric figures.

I found a website that further explains Pick’s Theorem. Notice that some of the letters have been changed around but they still apply the same concepts:

http://www.cut-the-knot.org/ctk/Pick_proof.shtml

I also found a very helpful video that demonstrates the process of Pick’s Theorem:

http://www.youtube.com/watch?v=XaviJAIZoss

From this lesson I learned a different method on how to find the areas and perimeters of geometric figures. The activities taught me how the figures can be broken up into squares, triangles, and trapezoids. I really enjoyed doing the rubber-band activity. It helped me get a better grasp of the concepts. Children will also find this activity fun and because they are more actively involved. This is an excellent activity for students who are visually disoriented, visual, or hands-on-learners.