Introduction
Consider the occupation of an architect who designs buildings. They have to draw a diagram long before getting started with construction. You could do this by using graph paper to sketch the layout of a building. This is an example of using the coordinate plane in real life.
We will review the coordinate plane and how to find the distance to get started. Do you remember the distance formula?
Go to GeoGebra: ACCESS - Triangle Perimeter Calculations. See if you can figure out how to find the perimeter of the triangles using their coordinates only.
Following successful completion of this lesson, students will be able to...
- Find the perimeter and area of triangles in a Coordinate Plane
Essential Questions
- What are the differences between isosceles, scalene, and equilateral triangles?
- What are the differences between acute, right, and obtuse triangles?
- How do you find the perimeter and area of a triangle in the coordinate plane?
- What information is needed to show that two triangles are congruent?
- What information is needed to show that two figures are congruent?
Enduring Understandings
- The symmetry of polygons can be described in rotations and reflections.
- The sum of the interior angles of any triangle is a constant.
- The perimeter and area of a polygon can be calculated using its x and y coordinates.
- Congruence can be used to prove theorems about triangles.
The above objectives correspond with the Alabama Course of Study: Geometry standard: 18.