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Finding the Fourth Proportional to 709.88, 979.64 and 399.38

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Solution

The fourth proportional to 709.88, 979.64 and 399.38 is: 551.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.88 : 979.64 = 399.38 : x
  2. Step 2: Convert to fraction form
    709.88/979.64 = 399.38/x
  3. Step 3: Cross multiply
    709.88x = 979.64 × 399.38
  4. Step 4: Simplify right side
    709.88x = 391,241.73
  5. Step 5: Solve for x
    x = 391,241.73/709.88
  6. Step 6: Final answer
    x = 551.14

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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.