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Finding the Fourth Proportional to 661.12, 991.92 and 553.12

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Solution

The fourth proportional to 661.12, 991.92 and 553.12 is: 829.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    661.12 : 991.92 = 553.12 : x
  2. Step 2: Convert to fraction form
    661.12/991.92 = 553.12/x
  3. Step 3: Cross multiply
    661.12x = 991.92 × 553.12
  4. Step 4: Simplify right side
    661.12x = 548,650.79
  5. Step 5: Solve for x
    x = 548,650.79/661.12
  6. Step 6: Final answer
    x = 829.88

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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.