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Finding the Fourth Proportional to 391.18, 585.80 and 387.12

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Solution

The fourth proportional to 391.18, 585.80 and 387.12 is: 579.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.18 : 585.80 = 387.12 : x
  2. Step 2: Convert to fraction form
    391.18/585.80 = 387.12/x
  3. Step 3: Cross multiply
    391.18x = 585.80 × 387.12
  4. Step 4: Simplify right side
    391.18x = 226,774.90
  5. Step 5: Solve for x
    x = 226,774.90/391.18
  6. Step 6: Final answer
    x = 579.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.