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Finding the Fourth Proportional to 618.68, 853.42 and 394.21

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Solution

The fourth proportional to 618.68, 853.42 and 394.21 is: 543.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    618.68 : 853.42 = 394.21 : x
  2. Step 2: Convert to fraction form
    618.68/853.42 = 394.21/x
  3. Step 3: Cross multiply
    618.68x = 853.42 × 394.21
  4. Step 4: Simplify right side
    618.68x = 336,423.58
  5. Step 5: Solve for x
    x = 336,423.58/618.68
  6. Step 6: Final answer
    x = 543.77

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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.