CCSS.Math.Content.HSG-MG.A.3

MathGrades 9–12Modeling with Geometry

The standard

Apply geometric methods to solve design problems (e.g., designing an object or structure to satisfy physical constraints or minimize cost; working with typographic grid systems based on ratios).

Common Core State Standards for Mathematics

What this standard means

Students need to use geometry as a design tool, not just solve given diagrams. They should choose shapes, measurements, scale factors, area, volume, surface area, ratios, and constraints to make a design work. They also need to compare options, explain tradeoffs, and justify a choice with calculations.

Mastery looks like a student saying, “Here are the limits, here is my model, here is why this design fits and costs less.” Common sticking points are ignoring units, forgetting scale, using formulas without checking if they match the object, and treating constraints as extra details instead of requirements.

Ways to teach it

  • Hands-on activity: Give teams cardboard, tape, and a fixed surface-area limit to build the largest possible open-top container.
  • Writing prompt: Explain which geometry choices matter most when designing a phone stand that must hold two phone sizes without tipping.
  • Quick assessment: Show two garden bed designs with dimensions and material costs, then ask students to choose and justify the cheaper valid design.
  • Real-world connection: Have students analyze a cereal box redesign that keeps volume the same while reducing cardboard used.

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Related standards

Standard text verified against corestandards.org on July 10, 2026.

Page updated July 10, 2026.

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