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Finding the Fourth Proportional to 981.80, 1,470.30 and 938.60

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Solution

The fourth proportional to 981.80, 1,470.30 and 938.60 is: 1,405.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.80 : 1,470.30 = 938.60 : x
  2. Step 2: Convert to fraction form
    981.80/1,470.30 = 938.60/x
  3. Step 3: Cross multiply
    981.80x = 1,470.30 × 938.60
  4. Step 4: Simplify right side
    981.80x = 1,380,023.58
  5. Step 5: Solve for x
    x = 1,380,023.58/981.80
  6. Step 6: Final answer
    x = 1,405.61

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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.