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Finding the Fourth Proportional to 981.80, 1,471.60 and 425.87

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Solution

The fourth proportional to 981.80, 1,471.60 and 425.87 is: 638.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.80 : 1,471.60 = 425.87 : x
  2. Step 2: Convert to fraction form
    981.80/1,471.60 = 425.87/x
  3. Step 3: Cross multiply
    981.80x = 1,471.60 × 425.87
  4. Step 4: Simplify right side
    981.80x = 626,702.93
  5. Step 5: Solve for x
    x = 626,702.93/981.80
  6. Step 6: Final answer
    x = 638.32

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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.