Mathematics
Grade 10
15 min
Multiply fractions by whole numbers: set 2
Multiply fractions by whole numbers: set 2
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1
Introduction & Learning Objectives
Learning Objectives
Calculate the volume of prisms and pyramids when dimensions are fractional and multipliers are whole numbers.
Determine the surface area of composite 3D figures involving fractional lengths and a whole number of components.
Apply the multiplication of fractions by whole numbers to solve problems involving the density and mass of 3D objects.
Analyze how scaling a 3D figure's dimensions by a whole number factor affects its volume when the original volume is a fraction.
Solve multi-step word problems involving rates of change (e.g., filling a container) that require multiplying fractions by whole numbers within a 3D geometry context.
Compute the total volume of a set of multiple, identical 3D objects with fractional dimensions.
How do manufacturers calc...
2
Key Concepts & Vocabulary
TermDefinitionExample
Volume of a PrismThe amount of space a prism occupies, calculated by multiplying the area of its base (B) by its height (h). The calculation often involves a fractional area or height multiplied by a whole number.A rectangular prism with a base area of 9/2 cm² and a height of 10 cm has a volume of 10 * (9/2) = 90/2 = 45 cm³.
Volume of a Pyramid or ConeThe space occupied by a pyramid or cone, calculated as one-third of the product of its base area (B) and height (h). The formula itself introduces a fraction (1/3) that is often multiplied by whole numbers.A pyramid with a base area of 24 m² and a height of 7/2 m has a volume of (1/3) * 24 * (7/2) = 8 * (7/2) = 56/2 = 28 m³.
Surface Area of Multiple ObjectsThe total exposed area of a set of objects. For 'n' id...
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Core Formulas
Multiplying a Whole Number by a Fraction
n \cdot \frac{a}{b} = \frac{n \cdot a}{b}
To multiply a whole number (n) by a fraction (a/b), multiply the whole number by the numerator (a) and keep the denominator (b) the same. This is the core operation for finding total volumes or scaling fractional dimensions.
Volume of a Prism or Cylinder
V = B \cdot h
The volume (V) is the product of the base area (B) and the height (h). Use this when, for example, B is a fraction and h is a whole number, or vice versa.
Volume Scaling Principle
V_{new} = k^3 \cdot V_{original}
If a 3D figure's linear dimensions are all multiplied by a whole number scaling factor (k), the new volume is k-cubed times the original volume. This is a key application of multiplying a whole number (k³) b...
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Easy
A set of 4 identical cubes are stacked on a shelf. If each cube has a side length of 1/2 inch, what is the total volume of all 4 cubes combined?
A.1/2 in³
B.1 in³
C.2 in³
D.4/8 in³
Easy
A rectangular prism has a base area of 15 cm². Its height is 2/3 cm. What is the volume of the prism?
A.10 cm³
B.30/45 cm³
C.45/2 cm³
D.15 cm³
Easy
What is the volume of a pyramid with a base area of 18 m² and a height of 1/2 m?
A.9 m³
B.6 m³
C.3 m³
D.18 m³
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