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Finding the Fourth Proportional to 391.61, 585.28 and 309.59

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Solution

The fourth proportional to 391.61, 585.28 and 309.59 is: 462.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.61 : 585.28 = 309.59 : x
  2. Step 2: Convert to fraction form
    391.61/585.28 = 309.59/x
  3. Step 3: Cross multiply
    391.61x = 585.28 × 309.59
  4. Step 4: Simplify right side
    391.61x = 181,197.52
  5. Step 5: Solve for x
    x = 181,197.52/391.61
  6. Step 6: Final answer
    x = 462.70

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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.