Math Problem Statement

The diagram below shows one diagonal of a cube. If the length of the diagonal is √12 units, then the surface area of the cube is?

Solution

Let's solve the problem.

The problem states:

  • The diagonal of a cube has a length of 12\sqrt{12}.
  • We need to find the surface area of the cube.

Step 1: Formula for the space diagonal of a cube

The diagonal of a cube can be calculated using the formula: d=a3d = a\sqrt{3} where aa is the side length of the cube, and dd is the diagonal.


Step 2: Solve for the side length

Here, the given diagonal d=12d = \sqrt{12}. Substituting into the formula: 12=a3\sqrt{12} = a\sqrt{3} Solve for aa by dividing both sides by 3\sqrt{3}: a=123a = \frac{\sqrt{12}}{\sqrt{3}} Simplify 123\frac{\sqrt{12}}{\sqrt{3}}: a=123=4=2a = \sqrt{\frac{12}{3}} = \sqrt{4} = 2 Thus, the side length of the cube is a=2a = 2 units.


Step 3: Surface area of the cube

The surface area SS of a cube is given by: S=6a2S = 6a^2 Substitute a=2a = 2: S=6(22)=6×4=24S = 6(2^2) = 6 \times 4 = 24


Final Answer:

The surface area of the cube is: 24 square units\boxed{24 \text{ square units}}


Would you like a detailed explanation of any step, or have additional questions?


Related Questions:

  1. How do you derive the formula for the space diagonal of a cube?
  2. What is the volume of the cube if the side length is 2 units?
  3. If the diagonal were 27\sqrt{27}, what would the surface area of the cube be?
  4. How would this problem change if it were a rectangular prism instead of a cube?
  5. Can the diagonal of a cube ever be an integer? Why or why not?

Tip:

To simplify square roots, try factoring into perfect squares (e.g., 12=43=23\sqrt{12} = \sqrt{4 \cdot 3} = 2\sqrt{3}).

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Math Problem Analysis

Mathematical Concepts

Geometry
Surface Area
Cube Properties

Formulas

Diagonal of a cube: d = a√3
Surface area of a cube: S = 6a^2

Theorems

Pythagorean Theorem (used in deriving the diagonal formula)

Suitable Grade Level

Grades 8-10