Florida Grade 5 Math · Geometric Reasoning

MA.5.GR.2.1: Area and perimeter with fractions and decimals

What this Grade 5 benchmark means, worked examples, common mistakes, and a free printable worksheet.

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Download Free Worksheet (PDF)See worked examples

What Is Benchmark MA.5.GR.2.1?

In Grade 5, students find the perimeter and area of rectangles whose side lengths are fractions or decimals, using visual models and formulas.

Area = length × width, in square units. Perimeter = the distance around = 2 × (length + width), in regular units.

Official benchmarkFind the perimeter and area of a rectangle with fractional or decimal side lengths using visual models and formulas.

On the FAST test: part of the Grade 5 reporting category Geometric Reasoning, Measurement, and Data Analysis and Probability, which is about 23–29% of the test.

Worked Examples

Worked Example 1

Fraction Side Lengths

A rectangle is 312 ft long and 2 ft wide.

Rectangle 3 and 1/2 feet long and 2 feet wide.

1Area: 312 × 2 = 7 square feet.
2Perimeter: 2 × (312 + 2) = 2 × 512 = 11 feet.

Answer: Area 7 sq ft; perimeter 11 ft

Worked Example 2

Decimal Side Lengths

A rectangle is 4.5 m long and 2.2 m wide.

Rectangle 4.5 meters long and 2.2 meters wide.

1Area: 4.5 × 2.2 = 9.9 square meters.
2Perimeter: 2 × (4.5 + 2.2) = 2 × 6.7 = 13.4 meters.

Answer: Area 9.9 sq m; perimeter 13.4 m

Common Mistakes to Watch For

Mixing up area and perimeter

Wrong:Area of 4.5 m × 2.2 m = 13.4 m

13.4 m is the distance around (perimeter). Area multiplies: 4.5 × 2.2 = 9.9 square meters.

Adding only two sides for perimeter

Wrong:Perimeter = 312 + 2 = 512 ft

A rectangle has four sides: 312 + 2 + 312 + 2 = 11 ft.

Helpful Math Tip

Write the units every time. "Square feet" means area (inside), "feet" means perimeter (around).

Related Grade 5 Skills

MA.5.FR.2.2

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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.