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Finding the Fourth Proportional to 831.27, 1,245.82 and 420.18

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Solution

The fourth proportional to 831.27, 1,245.82 and 420.18 is: 629.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.27 : 1,245.82 = 420.18 : x
  2. Step 2: Convert to fraction form
    831.27/1,245.82 = 420.18/x
  3. Step 3: Cross multiply
    831.27x = 1,245.82 × 420.18
  4. Step 4: Simplify right side
    831.27x = 523,472.27
  5. Step 5: Solve for x
    x = 523,472.27/831.27
  6. Step 6: Final answer
    x = 629.73

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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.