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Finding the Fourth Proportional to 831.10, 1,245.30 and 612.40

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Solution

The fourth proportional to 831.10, 1,245.30 and 612.40 is: 917.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.10 : 1,245.30 = 612.40 : x
  2. Step 2: Convert to fraction form
    831.10/1,245.30 = 612.40/x
  3. Step 3: Cross multiply
    831.10x = 1,245.30 × 612.40
  4. Step 4: Simplify right side
    831.10x = 762,621.72
  5. Step 5: Solve for x
    x = 762,621.72/831.10
  6. Step 6: Final answer
    x = 917.61

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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.