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Finding the Fourth Proportional to 405.90, 608.18 and 390.92

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Solution

The fourth proportional to 405.90, 608.18 and 390.92 is: 585.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.90 : 608.18 = 390.92 : x
  2. Step 2: Convert to fraction form
    405.90/608.18 = 390.92/x
  3. Step 3: Cross multiply
    405.90x = 608.18 × 390.92
  4. Step 4: Simplify right side
    405.90x = 237,749.73
  5. Step 5: Solve for x
    x = 237,749.73/405.90
  6. Step 6: Final answer
    x = 585.73

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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.