A right pyramid is on a regular hexagonal base. Each side of the base is $10\text{ m}$ and the height is $60\text{ m}$. The volume of the pyramid is
Aptitude
Volume and Surface Area
Difficulty: Medium
Choose an option
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A$5000\text{ m}^3$
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B$5100\text{ m}^3$
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C$5195\text{ m}^3$
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D$5196\text{ m}^3$
Answer
Correct Answer: $5196\text{ m}^3$
Explanation
### Concept & Formula
The area of a regular hexagon can be found by treating it as six equilateral triangles.
$$ \text{Base Area} = 6 \times \frac{\sqrt{3}}{4} \times a^2 $$
$$ \text{Volume} = \frac{1}{3} \times \text{Base Area} \times h $$
### Step-by-Step Solution
1. **Given:**
- Side of hexagonal base, $a = 10\text{ m}$
- Height, $h = 60\text{ m}$
2. **Calculate Base Area:**
- $\text{Base Area} = 6 \times \frac{\sqrt{3}}{4} \times (10)^2$
- $\text{Base Area} = 6 \times \frac{\sqrt{3}}{4} \times 100 = 6 \times 25\sqrt{3} = 150\sqrt{3}\text{ m}^2$
3. **Calculate Volume:**
- $\text{Volume} = \frac{1}{3} \times 150\sqrt{3} \times 60$
- $\text{Volume} = 50\sqrt{3} \times 60 = 3000\sqrt{3}$
4. **Convert to Decimal:**
- Since $\sqrt{3} \approx 1.732$
- $\text{Volume} = 3000 \times 1.732 = 5196\text{ m}^3$
### Exam Strategy & Shortcut
Instead of multiplying large numbers, group them logically: $\frac{1}{3} \times 60 = 20$. Then $20 \times 150\sqrt{3} = 3000\sqrt{3}$. You can mentally shift the decimal place of $1.732$ three places to the right to get $1732$, and then multiply by $3$ to get $5196$.
### Common Pitfall
A common mistake is calculating the perimeter instead of the area of the hexagon, or forgetting the $\frac{1}{3}$ in the pyramid volume formula.
### Final Answer
Therefore, the correct answer is **$5196\text{ m}^3$**.