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Finding the Fourth Proportional to 620.78, 855.98 and 396.42

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Solution

The fourth proportional to 620.78, 855.98 and 396.42 is: 546.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.78 : 855.98 = 396.42 : x
  2. Step 2: Convert to fraction form
    620.78/855.98 = 396.42/x
  3. Step 3: Cross multiply
    620.78x = 855.98 × 396.42
  4. Step 4: Simplify right side
    620.78x = 339,323.31
  5. Step 5: Solve for x
    x = 339,323.31/620.78
  6. Step 6: Final answer
    x = 546.61

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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.