If the sides of a triangle be in the ratio 2 : 3 : 4, the ratio of the corresponding altitudes is
Aptitude
Area
Difficulty: Medium
Choose an option
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A6 : 5 : 3
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B4 : 5 : 6
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C5 : 4 : 3
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D6 : 4 : 3
Answer
Correct Answer: 6 : 4 : 3
Explanation
### Concept & Inverse Proportionality of Altitudes
For any given triangle, the area is constant regardless of which side is chosen as the base. Since $Area = \frac{1}{2} \times \text{base} \times \text{altitude}$, the altitude is inversely proportional to its corresponding base length.
### Step-by-Step Solution
* Let the area of the triangle be $A$.
* Let the sides (bases) be $2x$, $3x$, and $4x$.
* The corresponding altitudes are $h_1$, $h_2$, and $h_3$.
* Since area is constant: $\frac{1}{2}(2x)h_1 = \frac{1}{2}(3x)h_2 = \frac{1}{2}(4x)h_3 = A$.
* Therefore, $h_1 \propto \frac{1}{2}$, $h_2 \propto \frac{1}{3}$, and $h_3 \propto \frac{1}{4}$.
* The ratio of the altitudes is $\frac{1}{2} : \frac{1}{3} : \frac{1}{4}$.
* To simplify this into whole numbers, multiply by the Least Common Multiple (LCM) of the denominators (2, 3, and 4), which is 12.
* $\frac{12}{2} : \frac{12}{3} : \frac{12}{4} = 6 : 4 : 3$.
### Exam Strategy & Shortcut
When sides are given as a ratio $a : b : c$, the ratio of their corresponding altitudes is simply $\frac{1}{a} : \frac{1}{b} : \frac{1}{c}$. Find the LCM of $a, b, c$ and multiply it through to get the final integer ratio instantly.
### Common Pitfall
Reversing the direct ratio to $4 : 3 : 2$. Inverse ratios of three numbers do not work by simply reversing the order; you must use reciprocals.
### Final Answer
Therefore, the correct answer is **6 : 4 : 3**.