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Finding the Fourth Proportional to 820.12, 1,129.20 and 724.22

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Solution

The fourth proportional to 820.12, 1,129.20 and 724.22 is: 997.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.12 : 1,129.20 = 724.22 : x
  2. Step 2: Convert to fraction form
    820.12/1,129.20 = 724.22/x
  3. Step 3: Cross multiply
    820.12x = 1,129.20 × 724.22
  4. Step 4: Simplify right side
    820.12x = 817,789.22
  5. Step 5: Solve for x
    x = 817,789.22/820.12
  6. Step 6: Final answer
    x = 997.16

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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.