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Finding the Fourth Proportional to 708.87, 978.13 and 398.31

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Solution

The fourth proportional to 708.87, 978.13 and 398.31 is: 549.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.87 : 978.13 = 398.31 : x
  2. Step 2: Convert to fraction form
    708.87/978.13 = 398.31/x
  3. Step 3: Cross multiply
    708.87x = 978.13 × 398.31
  4. Step 4: Simplify right side
    708.87x = 389,598.96
  5. Step 5: Solve for x
    x = 389,598.96/708.87
  6. Step 6: Final answer
    x = 549.61

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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.