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Finding the Fourth Proportional to 985.92, 1,478.82 and 408.78

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Solution

The fourth proportional to 985.92, 1,478.82 and 408.78 is: 613.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    985.92 : 1,478.82 = 408.78 : x
  2. Step 2: Convert to fraction form
    985.92/1,478.82 = 408.78/x
  3. Step 3: Cross multiply
    985.92x = 1,478.82 × 408.78
  4. Step 4: Simplify right side
    985.92x = 604,512.04
  5. Step 5: Solve for x
    x = 604,512.04/985.92
  6. Step 6: Final answer
    x = 613.15

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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.