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Finding the Fourth Proportional to 708.71, 978.01 and 398.21

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Solution

The fourth proportional to 708.71, 978.01 and 398.21 is: 549.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.71 : 978.01 = 398.21 : x
  2. Step 2: Convert to fraction form
    708.71/978.01 = 398.21/x
  3. Step 3: Cross multiply
    708.71x = 978.01 × 398.21
  4. Step 4: Simplify right side
    708.71x = 389,447.48
  5. Step 5: Solve for x
    x = 389,447.48/708.71
  6. Step 6: Final answer
    x = 549.52

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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.