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Finding the Fourth Proportional to 709.39, 978.95 and 398.89

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Solution

The fourth proportional to 709.39, 978.95 and 398.89 is: 550.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.39 : 978.95 = 398.89 : x
  2. Step 2: Convert to fraction form
    709.39/978.95 = 398.89/x
  3. Step 3: Cross multiply
    709.39x = 978.95 × 398.89
  4. Step 4: Simplify right side
    709.39x = 390,495.59
  5. Step 5: Solve for x
    x = 390,495.59/709.39
  6. Step 6: Final answer
    x = 550.47

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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.