Find the Perimeter
Aligned to 3.MD.D.8 — Common Core State Standards for Mathematics.
What this lesson teaches
Perimeter is the distance all the way around a shape. Add up the lengths of every side to find it.
Worked example
A rectangle has sides of 4, 4, 2, and 2. Add them all: 4 + 4 + 2 + 2 = 12. The perimeter is 12 units.
Practice questions
- Find the perimeter of a square with sides of 5.
- A triangle has sides 3, 4, and 5. What is its perimeter?
- A rectangle has a perimeter of 10 and three sides of 3, 2, and 3. What is the missing side?
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Hallar el Perímetro
El perímetro es la distancia alrededor de toda una figura. Suma las longitudes de todos los lados para hallarlo.
Ejemplo: Un rectángulo tiene lados de 4, 4, 2 y 2. Súmalos todos: 4 + 4 + 2 + 2 = 12. El perímetro es 12 unidades.
More Measurement & Data lessons
Area3.MD.C.7Time, Mass, Liquid Volume, and Graphs3.MD.A.1Measure Mass and Volume3.MD.A.2Picture Graphs and Bar Graphs3.MD.B.3Measure Lengths and Line Plots3.MD.B.4What Is Area?3.MD.C.5
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