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Finding the Fourth Proportional to 664.39, 916.79 and 398.79

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Solution

The fourth proportional to 664.39, 916.79 and 398.79 is: 550.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.39 : 916.79 = 398.79 : x
  2. Step 2: Convert to fraction form
    664.39/916.79 = 398.79/x
  3. Step 3: Cross multiply
    664.39x = 916.79 × 398.79
  4. Step 4: Simplify right side
    664.39x = 365,604.69
  5. Step 5: Solve for x
    x = 365,604.69/664.39
  6. Step 6: Final answer
    x = 550.29

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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.