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Finding the Fourth Proportional to 618.50, 853.30 and 408.78

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Solution

The fourth proportional to 618.50, 853.30 and 408.78 is: 563.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    618.50 : 853.30 = 408.78 : x
  2. Step 2: Convert to fraction form
    618.50/853.30 = 408.78/x
  3. Step 3: Cross multiply
    618.50x = 853.30 × 408.78
  4. Step 4: Simplify right side
    618.50x = 348,805.66
  5. Step 5: Solve for x
    x = 348,805.66/618.50
  6. Step 6: Final answer
    x = 563.95

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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.