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Finding the Fourth Proportional to 709.12, 978.59 and 398.62

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Solution

The fourth proportional to 709.12, 978.59 and 398.62 is: 550.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.12 : 978.59 = 398.62 : x
  2. Step 2: Convert to fraction form
    709.12/978.59 = 398.62/x
  3. Step 3: Cross multiply
    709.12x = 978.59 × 398.62
  4. Step 4: Simplify right side
    709.12x = 390,083.55
  5. Step 5: Solve for x
    x = 390,083.55/709.12
  6. Step 6: Final answer
    x = 550.10

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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.