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Finding the Fourth Proportional to 620.08, 855.90 and 387.40

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Solution

The fourth proportional to 620.08, 855.90 and 387.40 is: 534.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    620.08 : 855.90 = 387.40 : x
  2. Step 2: Convert to fraction form
    620.08/855.90 = 387.40/x
  3. Step 3: Cross multiply
    620.08x = 855.90 × 387.40
  4. Step 4: Simplify right side
    620.08x = 331,575.66
  5. Step 5: Solve for x
    x = 331,575.66/620.08
  6. Step 6: Final answer
    x = 534.73

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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.