3.MD.C.7d Area of a Rectilinear Figure (Concrete Referents)

Evidence Statement 3.C.3-2- Base explanations/reasoning on concrete referents such as diagrams (whether provided in the prompt or constructed by the student in their response), connecting the diagrams to a written (symbolic) method.

The Dog Park

A model of a dog park is shown.

The rectilinear figure represents a model of a dog park. One area of the figure is 9 meters long and 7 meters wide. The other area of the figure is 10 meters long and 8 meters wide.

• Find the area, in square meters, of the dog park. 
• Explain your answer using an equation or equations. 
• Enter your answer and your explanation using your equation or equations in the space provided.

Student Copy

Scoring Rubric

Score of 3 Points

Student response includes each of the following 3 elements.

• Computation component- identifies the correct area of 143 square meters.
• Modeling component: Provides equations showing how to find the area of the two different sections of the dog park.
• Modeling component- Provides an equation to find the total area of the playground.     

Sample Student Response: The area of the dog park is 143 square meters. I found the area of the two sections of the dog park: 7 x 9 = 63 and 8 x 10 = 80. If you add the area of the two rectangles, you will find the area of the entire dog park. 63 + 80 = 143.

Notes: labeling the answer with square meters is not requires. However, if the student provides and incorrect label, the student cannot earn a score of 3 points.

Score of 2 Points

Student response includes 2 of the 3 elements. Or, the student does not compute the correct total area due to a computation error but provides a valid strategy and equations.

Score of 1 Point

Student response includes 1 of the 3 elements.

Score of 0 Points

Student response is incorrect or irrelevant.