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Finding the Fourth Proportional to 392.80, 586.40 and 391.84

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Solution

The fourth proportional to 392.80, 586.40 and 391.84 is: 584.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.80 : 586.40 = 391.84 : x
  2. Step 2: Convert to fraction form
    392.80/586.40 = 391.84/x
  3. Step 3: Cross multiply
    392.80x = 586.40 × 391.84
  4. Step 4: Simplify right side
    392.80x = 229,774.98
  5. Step 5: Solve for x
    x = 229,774.98/392.80
  6. Step 6: Final answer
    x = 584.97

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.