This lesson was conducted in Mr. Sloth's mathematics classes at Southside Middle School in Jacksonville, FL. in December, 1997. Students will understand the relationship and proportion between similar triangles. The similar triangles will be created using their own isosceles right triangle and the object whose height is being estimated. Apply the properties of similar isosceles right triangles to solve the problem of the length of an unknown side.
Lesson begins by having students make an isosceles right triangle out of construction paper.
A simple explanation and demonstration will allow them to do so in just a few minutes. On the overhead or chalk board begin a discussion of how to use similar triangles to estimate the unknown side of a similar triangle. Some time is necessary to explain to students how to use the triangle to sight to the top of the object. Then use the measuring tape to measure the distance from the student to the base of the object. Students can easily grasp that this distance is also the height of the object.