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Finding the Fourth Proportional to 709.98, 979.79 and 399.48

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Solution

The fourth proportional to 709.98, 979.79 and 399.48 is: 551.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.98 : 979.79 = 399.48 : x
  2. Step 2: Convert to fraction form
    709.98/979.79 = 399.48/x
  3. Step 3: Cross multiply
    709.98x = 979.79 × 399.48
  4. Step 4: Simplify right side
    709.98x = 391,404.51
  5. Step 5: Solve for x
    x = 391,404.51/709.98
  6. Step 6: Final answer
    x = 551.29

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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.