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Finding the Fourth Proportional to 709.38, 978.95 and 398.88

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Solution

The fourth proportional to 709.38, 978.95 and 398.88 is: 550.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.38 : 978.95 = 398.88 : x
  2. Step 2: Convert to fraction form
    709.38/978.95 = 398.88/x
  3. Step 3: Cross multiply
    709.38x = 978.95 × 398.88
  4. Step 4: Simplify right side
    709.38x = 390,483.58
  5. Step 5: Solve for x
    x = 390,483.58/709.38
  6. Step 6: Final answer
    x = 550.46

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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.