Lesson 11

Polygons

Let’s investigate polygons and their areas.

Problem 1

Select all the polygons.

Six figures labeled A, B, C, D, E, F.
A:

A

B:

B

C:

C

D:

D

E:

E

F:

F

Problem 2

Mark each vertex with a large dot. How many edges and vertices does this polygon have?

12 sided polygon resembling a star

Problem 3

Find the area of this trapezoid. Explain or show your strategy.

Trapezoid, bases 8 and 4 units. Height 3 units.

 

Problem 4

Lin and Andre used different methods to find the area of a regular hexagon with 6-inch sides. Lin decomposed the hexagon into six identical, equilateral triangles. Andre decomposed the hexagon into a rectangle and two triangles.

2 identical hexagons labeled Lin’s method and Andre’s method.

Find the area of the hexagon using each person’s method. Show your reasoning.

Problem 5

  1. Identify a base and a corresponding height that can be used to find the area of this triangle. Label the base \(b\) and the corresponding height \(h\).

    A triangle on a grid.
  2. Find the area of the triangle. Show your reasoning.

(From Unit 1, Lesson 9.)

Problem 6

On the grid, draw three different triangles with an area of 8 square units. Label the base and height of each triangle.

A blank coordinate plane with 16 evenly spaced horizontal units and 12 evenly spaced vertical units.
(From Unit 1, Lesson 10.)