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Finding the Fourth Proportional to 391.56, 584.40 and 339.90

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Solution

The fourth proportional to 391.56, 584.40 and 339.90 is: 507.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.56 : 584.40 = 339.90 : x
  2. Step 2: Convert to fraction form
    391.56/584.40 = 339.90/x
  3. Step 3: Cross multiply
    391.56x = 584.40 × 339.90
  4. Step 4: Simplify right side
    391.56x = 198,637.56
  5. Step 5: Solve for x
    x = 198,637.56/391.56
  6. Step 6: Final answer
    x = 507.30

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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.