Lesson 9: Practice Problems

Problem 1

Select all the polygons.

  1. The outline of an arrow pointing to the left.
  2. A enclosed shape with straight and curved lines.
  3. The outline of a star shape.
  4. A triangle with a section missing.
  5. The outline of a heart.
  6. A cube.

Problem 2

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

A blue enclosed star.

Problem 3

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

A trapezoid on a grid with bases of 4 and 8 and a height of 3.

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 triangles. Andre decomposed the hexagon into a rectangle and two triangles.

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

Two identical hexagons labeled “Lin’s method” and “Andre’s method”. Each hexagon has three sides labeled 6 inches and an arrow indicating total height labeled 10.4 inches. “Lin’s method” is divided into six equal triangles, and Andre’s method is decomposed into a rectangle made of lines extending from one side to the opposite side, with a triangle on either side of the rectangle.

Problem 5 From Unit 1 Lesson 8

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

    A triangle that has two vertices 11 units apart from one another horizontally, and a third vertex that is 2 units below the horizontal line and five units right of the left vertex and 6 units right of the left vertex.

  2. Find the area of the triangle. Show your reasoning.

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.