Florida Grade 3 Math · Geometric Reasoning

MA.3.GR.2.3: Perimeter and Area of Rectangles

What this Grade 3 benchmark means, worked examples, common mistakes, and a free printable worksheet.

Created by a Florida mom · Published by Tropical Learning LLC

Download Free Worksheet (PDF)See worked examples

What Is Benchmark MA.3.GR.2.3?

Students solve problems about both the perimeter (distance around) and the area (space inside) of rectangles with whole-number side lengths, using models and formulas. In Grade 3, all side lengths are given; students do not find missing side lengths.

Perimeter is measured in units (feet, centimeters). Area is measured in square units (square feet, square centimeters). Rectangles are no bigger than 12 units by 12 units.

Official benchmarkSolve mathematical and real-world problems involving the perimeter and area of rectangles with whole-number side lengths using a visual model and a formula.

On the FAST test: part of the Grade 3 reporting category Geometric Reasoning, Measurement, and Data Analysis and Probability, which is about 23–29% of the test.

Worked Examples

Worked Example 1

Fence and Soil

A garden is 8 feet long and 5 feet wide. How much fence goes around it? How much ground does it cover?

1Fence is the perimeter: 8 + 5 + 8 + 5 = 26
2Ground covered is the area: 8 × 5 = 40

Answer: Perimeter: 26 feet. Area: 40 square feet.

Worked Example 2

Same Area, Different Perimeter

Rectangle A is 6 units by 4 units. Rectangle B is 8 units by 3 units. Compare their areas and perimeters.

1Areas: 6 × 4 = 24 and 8 × 3 = 24, so the areas are equal.
2Perimeters: 6 + 4 + 6 + 4 = 20 and 8 + 3 + 8 + 3 = 22

Answer: Same area (24 square units); B has the greater perimeter (22 units)

Common Mistakes to Watch For

Using area when the question asks for the distance around

Wrong:Fence around a garden 8 feet by 5 feet: 8 × 5 = 40 feet.

Fence goes around the edge, so find the perimeter: 8 + 5 + 8 + 5 = 26 feet.

Mixing up the units

Wrong:The perimeter is 26 square feet.

Perimeter is a length, so it is 26 feet. Area uses square units.

Helpful Math Tip

Ask: "Are we going around the edge (perimeter) or covering the inside (area)?" before choosing what to calculate.

Related Grade 3 Skills

MA.3.GR.2.2

Area of Rectangles

MA.3.GR.2.4

Area and Perimeter of Composite Figures

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Independent Educational Platform. FastChomp is published by Tropical Learning LLC and is not affiliated with, sponsored by, or endorsed by the Florida Department of Education. FAST and Star assessment names are referenced for informational purposes only. FastChomp practice questions are original educational materials, not official Florida FAST assessment questions.