Area of Parallelograms and Triangles

Need an activity for teaching the Pythagorean Theorem? Geometry juniors apply the Pythagorean theorem to two triangles to determine a final calculation. 

Providing the first installment in a series devoted to the exploration of Heron's Formula, this video is a high-level experience that delves into a proof using algebra. It demonstrates a step-by-step process for finding the area of a...

Ensure a solid understanding of the components of a parallelogram. The instructor highlights the key concepts when determining the area of a parallelogram. He presents the formula used for parallelograms as images and as coordinates. 

The teacher explains how the formula for a triangle was determined. It is related to a parallelogram. What? The formula for the area of a triangle is derived from the area of a parallelogram? Seeing is believing, so watch this video to...

While the lesson plan focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can...

The formula for the area of a triangle is: area equals one half the base times the height. If you have been given these two values then all you need to do is plug them into the formula and solve. Don't forget to write the correct ending...

The teacher explains how the formula for a triangle was determined. It is related to a parallelogram. What? The formula for the area of a triangle is derived from the area of a parallelogram? Seeing is believing, so watch this video to...

Make math easier by showing the class that even formulas can be parallel — just explore the area of a parallelogram. Learners discover how to create a rectangle from a parallelogram, then make the connection that the same formula applies.

It's always nice to have a plan B. Pupils investigate an alternate formula for the area of a triangle that uses sine. A set of challenge questions shows how the new formula relates to the well-known formula of (1/2)bh.

Base times height or one half base times height ... area formulas are pretty predictable! Given the base and height dimensions of a triangle, a video lesson explains the process of finding the area. Learners have the opportunity to...