Lesson+4+-+Areas+of+Trapezoids

= Lesson #4 =

Title of lesson: Areas of Trapezoids
Description of lesson: Students will use what they've learned so far about finding the areas of rectangles and triangles to find the areas of trapezoids. Trapezoids can be broken into triangles and rectangles, so the students will use what they've learned so far not only to find the whole area of a trapezoid, but to understand the area formula that we typically use to find the area of a trapezoid.

Assignment: We will work as a large group, in small groups and individually to solve for the areas of various trapezoids. We'll begin the lesson with a warm-up problem where students will work individually to find the area of a triangle using what they learned in the previous lesson. After the students have been given 5 minutes to work individually, we will take 5 minutes to discuss the solution as a class.

A trapezoid will be displayed on the smartboard/promethean board and we will work as a group to break it into its separate pieces (two triangles and one rectangle). Once the trapezoid has been broken into pieces the students have already learned to work with, we will work together to find the area of each shape and add them together to find the total area of the trapezoid. This should take approximately 10 minutes. Another trapezoid will then be displayed on the board and the students will be divided into groups of 3-4 and asked to split the trapezoid into its smaller shapes and solve for the area. They will be given 10 minutes to work on this. After the students have had time to work in their groups, we will spend about 5 minutes discussing the solution as a class. Another trapezoid will then be displayed on the board and the students will be shown the area formula for finding a trapezoid (A = average of the lengths of the parallel sides x height) and how it relates to the way we broke the trapezoid into smaller shapes. We will then solve for the area of the trapezoid using the area formula.

For homework, the students will be assigned a short worksheet of practice problems and asked to blog about the lesson: what they understood, what they didn't understand, what they thought could have been done differently, etc.

Resources/materials needed: Students may use the textbook as an additional reference. We will be using the smartboard/promethean board during class and students will need to bring their notebooks, and a pencil. The worksheet will be posted on the class website along with the reference sheet for the lesson:



Watch this video for additional information using the formula for the area of a trapezoid:

media type="youtube" key="JvI3yDL89_A?rel=0" height="390" width="480"

Technology reflection: The reference document and the video posted on the lesson will reinforce learning. The reference document will provide the formulas used in class so that students can use them for their homework. It will also provide an explanation of how the formulas relate to each other, and provide parents with a source for information if they'd like to check or help with the students' homework. The video shows students a way in which the information for the day's lesson can be used to determine other information about the trapezoid.

Evaluation: I will need to focus on making sure all of the students' needs are met by the lesson and that no one is being left behind. I will need to make sure I keep on track in terms of timing so that we are able to cover the unit in the time allotted. I will also need to make sure I have a backup plan in place just in case there is a technical problem with any of the technology. For example, I'll need to make sure I have chalk or dry erase markers in case the smartboard/promethean board isn't working. I'll also need to make sure I have a few copies of the homework printed in case there are any problems with the class website or there are students who can't access the internet for some reason.