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Finding the Fourth Proportional to 664.86, 991.43 and 618.69

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Solution

The fourth proportional to 664.86, 991.43 and 618.69 is: 922.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.86 : 991.43 = 618.69 : x
  2. Step 2: Convert to fraction form
    664.86/991.43 = 618.69/x
  3. Step 3: Cross multiply
    664.86x = 991.43 × 618.69
  4. Step 4: Simplify right side
    664.86x = 613,389.37
  5. Step 5: Solve for x
    x = 613,389.37/664.86
  6. Step 6: Final answer
    x = 922.58

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.