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Finding the Fourth Proportional to 680.21, 938.55 and 392.70

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Solution

The fourth proportional to 680.21, 938.55 and 392.70 is: 541.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.21 : 938.55 = 392.70 : x
  2. Step 2: Convert to fraction form
    680.21/938.55 = 392.70/x
  3. Step 3: Cross multiply
    680.21x = 938.55 × 392.70
  4. Step 4: Simplify right side
    680.21x = 368,568.59
  5. Step 5: Solve for x
    x = 368,568.59/680.21
  6. Step 6: Final answer
    x = 541.85

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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.