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Finding the Fourth Proportional to 391.80, 540.72 and 281.64

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Solution

The fourth proportional to 391.80, 540.72 and 281.64 is: 388.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.80 : 540.72 = 281.64 : x
  2. Step 2: Convert to fraction form
    391.80/540.72 = 281.64/x
  3. Step 3: Cross multiply
    391.80x = 540.72 × 281.64
  4. Step 4: Simplify right side
    391.80x = 152,288.38
  5. Step 5: Solve for x
    x = 152,288.38/391.80
  6. Step 6: Final answer
    x = 388.69

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.