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Finding the Fourth Proportional to 831.20, 1,245.68 and 343.68

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Solution

The fourth proportional to 831.20, 1,245.68 and 343.68 is: 515.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.20 : 1,245.68 = 343.68 : x
  2. Step 2: Convert to fraction form
    831.20/1,245.68 = 343.68/x
  3. Step 3: Cross multiply
    831.20x = 1,245.68 × 343.68
  4. Step 4: Simplify right side
    831.20x = 428,115.30
  5. Step 5: Solve for x
    x = 428,115.30/831.20
  6. Step 6: Final answer
    x = 515.06

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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.