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Finding the Fourth Proportional to 831.92, 1,249.70 and 420.95

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Solution

The fourth proportional to 831.92, 1,249.70 and 420.95 is: 632.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.92 : 1,249.70 = 420.95 : x
  2. Step 2: Convert to fraction form
    831.92/1,249.70 = 420.95/x
  3. Step 3: Cross multiply
    831.92x = 1,249.70 × 420.95
  4. Step 4: Simplify right side
    831.92x = 526,052.86
  5. Step 5: Solve for x
    x = 526,052.86/831.92
  6. Step 6: Final answer
    x = 632.34

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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.