# Perimeter and Area of Triangles in the Cartesian Plane

##### This Perimeter and Area of Triangles in the Cartesian Plane lesson plan also includes:

Pupils figure out how to be resourceful when tasked with finding the area of a triangle knowing nothing but its endpoints. Beginning by exploring and decomposing a triangle, learners find the perimeter and area of a triangle. They then work with the coordinates of the vertices of the triangle to create a formula for the area of the triangle.

CCSS: Designed

##### Instructional Ideas

• Use graphing white boards as scholars explore the patterns in the triangles
##### Classroom Considerations

• Provide graph paper to individuals for them to use as they explore the examples in the lesson
• Uses the distance formula to determine lengths of sides of triangles on the coordinate plane
• The ninth lesson in a series of 15
##### Pros

• Provides teacher notes and questioning suggestions throughout the lesson
• Includes answer keys for the lesson, practice problem set, and opening and closing activities
##### Cons

• Quickly moves to abstract formulas; learners can find the indicated measures without using the formulas