Education
Area & Perimeter Calculator
Quick area and perimeter for the common shapes. Great as a teacher reference or homework checker.
Area
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- Perimeter / circumference
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- Formula
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- Diagonal
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FAQ
Why does a triangle need 3 sides? +
Area only needs base + height, but perimeter needs all three sides. We accept side c so perimeter is correct.
Trapezoid perimeter assumes isoceles legs? +
For non-isoceles trapezoids, perimeter math needs the actual leg lengths. This calc approximates by assuming symmetric legs.