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Finding the Fourth Proportional to 390.40, 585.17 and 207.61

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Solution

The fourth proportional to 390.40, 585.17 and 207.61 is: 311.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.40 : 585.17 = 207.61 : x
  2. Step 2: Convert to fraction form
    390.40/585.17 = 207.61/x
  3. Step 3: Cross multiply
    390.40x = 585.17 × 207.61
  4. Step 4: Simplify right side
    390.40x = 121,484.22
  5. Step 5: Solve for x
    x = 121,484.22/390.40
  6. Step 6: Final answer
    x = 311.18

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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.