Unit 1, Lesson 10
Bases and Heights of Triangles
Grade 6
Preparation
Lesson Narrative
In this lesson, students further their ability to identify and work with bases and heights in a triangle by:
- Drawing a triangle with a given area (reversing the reasoning process they have done so far).
- Learning to draw (not just to recognize) a segment to show the corresponding height for any given base.
The lesson also includes an optional activity, in which students learn to choose appropriate base-height pairs to enable area calculations. Because there are three possible pairs of bases and heights in any triangle, some care is needed in identifying the right combination of measurements. Some base-height pairs may be more practical or efficient to use than others, so it helps to be strategic in choosing a side to use as a base.
- Draw and label the height that corresponds to a given base of a triangle, making sure it is perpendicular to the base and the correct length.
- Evaluate (orally) the usefulness of different base-height pairs for finding the area of a given triangle.
Let’s use different base-height pairs to find the area of a triangle.
Required Materials
Activity 1
Activity 2
Activity 3
Required Preparation
For the digital version of the activity, acquire devices that can run the applet.
Each student especially needs an index card.
Each side of a polygon is called an edge.
The edges of this polygon are segments , , , , and .