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Finding the Fourth Proportional to 708.78, 978.18 and 394.12

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Solution

The fourth proportional to 708.78, 978.18 and 394.12 is: 543.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.78 : 978.18 = 394.12 : x
  2. Step 2: Convert to fraction form
    708.78/978.18 = 394.12/x
  3. Step 3: Cross multiply
    708.78x = 978.18 × 394.12
  4. Step 4: Simplify right side
    708.78x = 385,520.30
  5. Step 5: Solve for x
    x = 385,520.30/708.78
  6. Step 6: Final answer
    x = 543.92

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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.