Georgia 4.GSR.8.3
The Standard
Solve problems involving area and perimeter of composite rectangles involving whole numbers with known side lengths.
Georgia's K-12 Mathematics Standards · Identify and draw geometric objects, classify polygons based on properties, and solve problems involving area and perimeter of rectangular figures.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students split a composite rectangular figure into smaller rectangles, find each area, and add the parts. They trace the outside boundary and add its side lengths to find perimeter.
What Mastery Looks Like
- A student can split an L-shaped or stepped figure into nonoverlapping rectangles and add their areas correctly. The student finds perimeter by adding only the outside side lengths and labels units correctly.
Common Misconceptions
- Students may add interior dividing lines when finding perimeter. They may confuse square units with linear units or add areas before splitting the figure into rectangles.
How to Assess It
- On grid paper, shade a 7-by-5 rectangle, then remove a 3-by-2 corner. Find the area and perimeter, and show your work.
Lesson moves
Ways to Teach It
Build an L-shape with square tiles, split it into rectangles with yarn, then calculate its area and outside perimeter.
Ask students to explain in writing why an interior dividing line helps find area but does not count toward perimeter.
Play Match the Figure by pairing composite-rectangle cards with area and perimeter cards, then justify each match.
Design a dog run from two joined rectangles, then calculate the grass needed and fencing required.
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Printable 4.GSR.8.3 Worksheet
A ready-to-print activity worksheet aligned to 4.GSR.8.3, with an answer key for the teacher on its own page. No account needed.
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Related Standards
- 3.GSR.7.2
Determine the area of rectangles (or shapes composed of rectangles) presented in relevant problems by tiling and counting.
- 3.GSR.7
Identify area as a measurable attribute of rectangles and determine the area of a rectangle presented in real-life, mathematical problems.
- 6.NR.1
Solve relevant, mathematical problems involving operations with whole numbers, fractions, and decimal numbers.
- 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.
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