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Finding the Fourth Proportional to 398.86, 599.50 and 390.36

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Solution

The fourth proportional to 398.86, 599.50 and 390.36 is: 586.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.86 : 599.50 = 390.36 : x
  2. Step 2: Convert to fraction form
    398.86/599.50 = 390.36/x
  3. Step 3: Cross multiply
    398.86x = 599.50 × 390.36
  4. Step 4: Simplify right side
    398.86x = 234,020.82
  5. Step 5: Solve for x
    x = 234,020.82/398.86
  6. Step 6: Final answer
    x = 586.72

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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.