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Finding the Fourth Proportional to 621.70, 857.79 and 400.39

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Solution

The fourth proportional to 621.70, 857.79 and 400.39 is: 552.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.70 : 857.79 = 400.39 : x
  2. Step 2: Convert to fraction form
    621.70/857.79 = 400.39/x
  3. Step 3: Cross multiply
    621.70x = 857.79 × 400.39
  4. Step 4: Simplify right side
    621.70x = 343,447.94
  5. Step 5: Solve for x
    x = 343,447.94/621.70
  6. Step 6: Final answer
    x = 552.43

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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.