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Measurement - Volume of Rectangular Prisms

Grade 5IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Volume is defined as the amount of three-dimensional space an object occupies. To visualize this, imagine a hollow shoe box and consider how much water or sand is needed to fill it completely to the top.

A Rectangular Prism is a 3D solid with six faces, all of which are rectangles. It is defined by three specific dimensions: length (ll), width (ww), and height (hh). Visually, the length is the distance across the front, the width is the distance going back (depth), and the height is the distance from the bottom to the top.

The basic unit of volume is the Cubic Unit (unit3unit^3). This is represented visually as a small cube where the length, width, and height are all exactly 11 unit. Common units include cubic centimeters (cm3cm^3), cubic meters (m3m^3), and cubic inches (in3in^3).

Volume can be calculated by counting unit cubes. If you visualize a prism made of Lego bricks, you can find the volume by counting the total number of individual 1×1×11 \times 1 \times 1 blocks that make up the entire structure.

The Layering Method is a way to calculate volume by finding the Area of the Base (BB) first and then multiplying by the height. Imagine a single layer of paper on a desk (the base area); as you stack more sheets of paper on top, the height increases, creating a 3D volume.

The Relationship between Area and Volume: Area is two-dimensional (length×widthlength \times width) and measured in square units (units2units^2), while Volume is three-dimensional (length×width×heightlength \times width \times height) and measured in cubic units (units3units^3).

Additive Volume applies to composite 3D shapes. If you have an L-shaped building, you can visually 'cut' the shape into two separate rectangular prisms, calculate the volume of each part individually, and then add those volumes together to find the total.

📐Formulae

V=l×w×hV = l \times w \times h

V=B×hV = B \times h

B=l×wB = l \times w

Height=VB\text{Height} = \frac{V}{B}

Base Area (B)=Vh\text{Base Area (B)} = \frac{V}{h}

💡Examples

Problem 1:

Calculate the volume of a rectangular juice box that has a length of 6 cm6 \text{ cm}, a width of 4 cm4 \text{ cm}, and a height of 10 cm10 \text{ cm}.

Solution:

V=l×w×hV = l \times w \times h V=6 cm×4 cm×10 cmV = 6 \text{ cm} \times 4 \text{ cm} \times 10 \text{ cm} V=24 cm2×10 cmV = 24 \text{ cm}^2 \times 10 \text{ cm} V=240 cm3V = 240 \text{ cm}^3

Explanation:

To solve this, identify the three dimensions: l=6l=6, w=4w=4, and h=10h=10. Multiply the length and width first to find the area of the base (24 cm224 \text{ cm}^2), then multiply that result by the height to find the total cubic space.

Problem 2:

A storage container has a total volume of 120 m3120 \text{ m}^3. If the area of the base is 30 m230 \text{ m}^2, what is the height of the container?

Solution:

V=B×hV = B \times h 120=30×h120 = 30 \times h h=12030h = \frac{120}{30} h=4 mh = 4 \text{ m}

Explanation:

In this problem, we are given the Volume (VV) and the Base Area (BB). Since V=B×hV = B \times h, we can find the missing height by dividing the total volume by the area of the base.