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Finding the Fourth Proportional to 390.39, 585.05 and 287.73

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Solution

The fourth proportional to 390.39, 585.05 and 287.73 is: 431.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.39 : 585.05 = 287.73 : x
  2. Step 2: Convert to fraction form
    390.39/585.05 = 287.73/x
  3. Step 3: Cross multiply
    390.39x = 585.05 × 287.73
  4. Step 4: Simplify right side
    390.39x = 168,336.44
  5. Step 5: Solve for x
    x = 168,336.44/390.39
  6. Step 6: Final answer
    x = 431.20

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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.