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Finding the Fourth Proportional to 621.28, 857.76 and 385.47

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Solution

The fourth proportional to 621.28, 857.76 and 385.47 is: 532.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.28 : 857.76 = 385.47 : x
  2. Step 2: Convert to fraction form
    621.28/857.76 = 385.47/x
  3. Step 3: Cross multiply
    621.28x = 857.76 × 385.47
  4. Step 4: Simplify right side
    621.28x = 330,645.41
  5. Step 5: Solve for x
    x = 330,645.41/621.28
  6. Step 6: Final answer
    x = 532.20

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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.