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Finding the Fourth Proportional to 660.78, 991.77 and 621.09

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Solution

The fourth proportional to 660.78, 991.77 and 621.09 is: 932.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.78 : 991.77 = 621.09 : x
  2. Step 2: Convert to fraction form
    660.78/991.77 = 621.09/x
  3. Step 3: Cross multiply
    660.78x = 991.77 × 621.09
  4. Step 4: Simplify right side
    660.78x = 615,978.43
  5. Step 5: Solve for x
    x = 615,978.43/660.78
  6. Step 6: Final answer
    x = 932.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.