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Finding the Fourth Proportional to 709.41, 978.98 and 398.91

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Solution

The fourth proportional to 709.41, 978.98 and 398.91 is: 550.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.41 : 978.98 = 398.91 : x
  2. Step 2: Convert to fraction form
    709.41/978.98 = 398.91/x
  3. Step 3: Cross multiply
    709.41x = 978.98 × 398.91
  4. Step 4: Simplify right side
    709.41x = 390,522.92
  5. Step 5: Solve for x
    x = 390,522.92/709.41
  6. Step 6: Final answer
    x = 550.49

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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.