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Finding the Fourth Proportional to 680.20, 938.78 and 418.40

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Solution

The fourth proportional to 680.20, 938.78 and 418.40 is: 577.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.20 : 938.78 = 418.40 : x
  2. Step 2: Convert to fraction form
    680.20/938.78 = 418.40/x
  3. Step 3: Cross multiply
    680.20x = 938.78 × 418.40
  4. Step 4: Simplify right side
    680.20x = 392,785.55
  5. Step 5: Solve for x
    x = 392,785.55/680.20
  6. Step 6: Final answer
    x = 577.46

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.