Volume with Fractional Edges
Aligned to 6.G.A.2 — Common Core State Standards for Mathematics.
What this lesson teaches
Volume of a right rectangular prism is length × width × height, and it works even when the edges are fractions. You can also use V = B × h, where B is the area of the base.
Worked examples
Example 1
A box is 1/2 ft by 3/4 ft by 2 ft. Volume = 1/2 × 3/4 × 2 = 6/8 = 3/4 cubic foot.
Example 2
A box 2/3 ft by 1/2 ft by 3 ft: 2/3 × 1/2 × 3 = 6/6 = 1 cubic foot.
Example 3
Count the cubes instead: a 1/2-inch cube is 1/8 of a cubic inch, so 24 of them fill 3 cubic inches.
Practice questions
- Find the volume of a prism 2/3 m by 3 m by 1/2 m.
- A base has area 5/6 square foot and height 4 ft. Find the volume using V = Bh.
- A fish tank measures 1 1/2 ft by 1 ft by 3/4 ft. What is its volume?
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
Volumen con Aristas Fraccionarias
El volumen de un prisma rectangular recto es largo × ancho × altura, y funciona incluso cuando las aristas son fracciones. También puedes usar V = B × h, donde B es el área de la base.
Ejemplo 1: Una caja mide 1/2 pie por 3/4 pie por 2 pies. Volumen = 1/2 × 3/4 × 2 = 6/8 = 3/4 de pie cúbico.
Ejemplo 2: Una caja de 2/3 pie por 1/2 pie por 3 pies: 2/3 × 1/2 × 3 = 6/6 = 1 pie cúbico.
Ejemplo 3: Cuenta los cubos en su lugar: un cubo de 1/2 pulgada es 1/8 de pulgada cúbica, así que 24 de ellos llenan 3 pulgadas cúbicas.
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