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Finding the Fourth Proportional to 661.20, 911.31 and 439.76

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Solution

The fourth proportional to 661.20, 911.31 and 439.76 is: 606.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.20 : 911.31 = 439.76 : x
  2. Step 2: Convert to fraction form
    661.20/911.31 = 439.76/x
  3. Step 3: Cross multiply
    661.20x = 911.31 × 439.76
  4. Step 4: Simplify right side
    661.20x = 400,753.13
  5. Step 5: Solve for x
    x = 400,753.13/661.20
  6. Step 6: Final answer
    x = 606.10

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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.