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Finding the Fourth Proportional to 708.78, 978.13 and 394.05

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Solution

The fourth proportional to 708.78, 978.13 and 394.05 is: 543.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.78 : 978.13 = 394.05 : x
  2. Step 2: Convert to fraction form
    708.78/978.13 = 394.05/x
  3. Step 3: Cross multiply
    708.78x = 978.13 × 394.05
  4. Step 4: Simplify right side
    708.78x = 385,436.29
  5. Step 5: Solve for x
    x = 385,436.29/708.78
  6. Step 6: Final answer
    x = 543.80

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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.