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Finding the Fourth Proportional to 831.81, 1,247.72 and 398.86

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Solution

The fourth proportional to 831.81, 1,247.72 and 398.86 is: 598.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.81 : 1,247.72 = 398.86 : x
  2. Step 2: Convert to fraction form
    831.81/1,247.72 = 398.86/x
  3. Step 3: Cross multiply
    831.81x = 1,247.72 × 398.86
  4. Step 4: Simplify right side
    831.81x = 497,663.60
  5. Step 5: Solve for x
    x = 497,663.60/831.81
  6. Step 6: Final answer
    x = 598.29

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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.