---
title: "3.GSR.8: Perimeter of Polygons (Georgia Mathematics standard)"
code: 3.GSR.8
cite_as: Georgia Standards of Excellence, Mathematics, 3.GSR.8
subject: math
grades:
  - grade-3
language: en
canonical_url: https://georgiahomeroom.org/standards/code/3.GSR.8
md_url: https://georgiahomeroom.org/standards/code/3.GSR.8.md
alternate_language_url: https://georgiahomeroom.org/es/standards/code/3.GSR.8.md
source_url: https://case.georgiastandards.org/ims/case/v1p1/CFDocuments/e9dd7229-3558-4df2-85c6-57b8938f6180
source_last_changed: 2024-10-09
data_built: 2026-09-18
publisher: Georgia Homeroom, a free public-interest project of Georgia Civic Data. Not affiliated with or endorsed by the Georgia Department of Education or any school district.
up: https://georgiahomeroom.org/standards/math/grade-3.md
index: https://georgiahomeroom.org/standards/index.md
---

# 3.GSR.8: Perimeter of Polygons

Determine the perimeter of a polygon presented in real-life, mathematical problems.

- Subject: Mathematics
- Appears in: Grade 3, https://georgiahomeroom.org/standards/math/grade-3.md

## Expectations

- **3.GSR.8.1**: Determine the perimeter of a polygon and explain that the perimeter represents the distance around a polygon. Solve problems involving perimeters of polygons.
- **3.GSR.8.2**: Investigate and describe how rectangles with the same perimeter can have different areas or how rectangles with the same area can have different perimeters.

## Georgia Milestones coverage

- Mathematics Grade 3 (EOG). Geometric & Spatial Reasoning. Determine the perimeter of a polygon presented in real-life, mathematical problems. (about 14% of the test; 8 points; shared with other standards, so count these points once and never add them up per standard)

## What mastery looks like

Georgia's Achievement Level Descriptors. The levels are cumulative: each includes the ones before it. Proficient is on grade level.

- **Beginning**: Know that perimeter is a measure of distance around a polygon.
- **Developing**: Determine the perimeters of polygons with given side lengths.
- **Proficient**: Solve real-life problems involving perimeters of polygons, including finding missing side lengths. Identify rectangles that have the same perimeter but different areas or the same area but different perimeters.
- **Distinguished**: Solve complex multi-step problems involving the perimeters of polygons, and explain how rectangles can have the same perimeter but different areas or the same area but different perimeters.

## The same standard across grades

- Kindergarten, K.GSR.8: Identify, describe, and compare basic shapes encountered in the environment, and form two-dimensional shapes and three-dimensional figures. https://georgiahomeroom.org/standards/code/K.GSR.8.md
- **Grade 3, 3.GSR.8 (this standard)**: Determine the perimeter of a polygon presented in real-life, mathematical problems.
- Grade 4, 4.GSR.8: Identify and draw geometric objects, classify polygons based on properties, and solve problems involving area and perimeter of rectangular figures. https://georgiahomeroom.org/standards/code/4.GSR.8.md
- Grade 5, 5.GSR.8: Examine properties of polygons and rectangular prisms, classify polygons by their properties, and discover volume of right rectangular prisms. https://georgiahomeroom.org/standards/code/5.GSR.8.md
- Grade 8, 8.GSR.8: Solve contextual, geometric problems involving the Pythagorean Theorem and the volume of geometric figures to explain real phenomena. https://georgiahomeroom.org/standards/code/8.GSR.8.md

Source: Georgia Standards of Excellence, published by the Georgia Department of Education at case.georgiastandards.org.