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Finding the Fourth Proportional to 421.87, 582.02 and 311.61

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Solution

The fourth proportional to 421.87, 582.02 and 311.61 is: 429.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.87 : 582.02 = 311.61 : x
  2. Step 2: Convert to fraction form
    421.87/582.02 = 311.61/x
  3. Step 3: Cross multiply
    421.87x = 582.02 × 311.61
  4. Step 4: Simplify right side
    421.87x = 181,363.25
  5. Step 5: Solve for x
    x = 181,363.25/421.87
  6. Step 6: Final answer
    x = 429.90

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.