Education Technology

Jack’s Tile Problem – Exploring the Area Rule for Triangles

Published on 09/10/2013

Activity Overview

In this activity, students change the shape of a triangle and capture the dimensions into a spreadsheet. They then explore and compare the two rules for the area of a triangle: Area = 1/2.b.h and Area = 1/2.a.b.sin(C)

Objectives

The objective of this activity is to show students how the area of a triangle formula Area = 1/2.a.b.sin(C) can be used to find the area of non-right angle triangles.

Vocabulary

area
triangle
non-right angle

About the Lesson

In this activity, students copy a TI-Nspire document onto their handhelds. They then change the shape of a triangle and capture the dimensions into a spreadsheet. In the first part of the activity, they use the rule Area = 1/2.b.h to confirm the areas of the triangles. In the second part of the activity, they use the rule Area = 1/2.a.b.sin(C) to verify the areas. They finish the activity by moving parts of a triangle to learn why both formulas arrive at the same result.