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Finding the Fourth Proportional to 831.94, 1,247.94 and 420.58

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Solution

The fourth proportional to 831.94, 1,247.94 and 420.58 is: 630.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.94 : 1,247.94 = 420.58 : x
  2. Step 2: Convert to fraction form
    831.94/1,247.94 = 420.58/x
  3. Step 3: Cross multiply
    831.94x = 1,247.94 × 420.58
  4. Step 4: Simplify right side
    831.94x = 524,853.15
  5. Step 5: Solve for x
    x = 524,853.15/831.94
  6. Step 6: Final answer
    x = 630.88

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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.