Unit 7, Lesson 15
Shapes in the Coordinate Plane
Grade 6
15.1
Warm-up
Draw a figure in the coordinate plane with at least three of the following properties:
- 6 vertices
- Exactly 1 pair of parallel sides
- At least 1 right angle
- 2 sides with the same length
15.3
Activity
The diagram shows Andre’s route through a maze. He started from the lower right entrance.
- What are the coordinates of the first two and the last two points of his route?
- How far did he walk from his starting point to his ending point? Explain or show your reasoning.
Student Lesson Summary
Coordinates can be used to find the lengths of segments in the coordinate plane.
Coordinate plane, origin O, axes labeled by ones. Segments connecting, in order, (negative 2 comma 2), (4 comma 2), (4 comma negative 1), (1 comma negative 1), (1 comma negative 4), (negative 2 comma negative 4), (negative 2 comma 2).
For example, we can find the perimeter of this polygon by finding the sum of its side lengths. Starting from and moving clockwise, we can see that the lengths of the segments are 6, 3, 3, 3, 3, and 6 units. The perimeter is therefore 24 units.
In general:
- If two points have the same -coordinate, they will be on the same vertical line, and we can find the distance between them.
- If two points have the same -coordinate, they will be on the same horizontal line, and we can find the distance between them.
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