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Finding the Fourth Proportional to 820.98, 1,231.90 and 547.20

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Solution

The fourth proportional to 820.98, 1,231.90 and 547.20 is: 821.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.98 : 1,231.90 = 547.20 : x
  2. Step 2: Convert to fraction form
    820.98/1,231.90 = 547.20/x
  3. Step 3: Cross multiply
    820.98x = 1,231.90 × 547.20
  4. Step 4: Simplify right side
    820.98x = 674,095.68
  5. Step 5: Solve for x
    x = 674,095.68/820.98
  6. Step 6: Final answer
    x = 821.09

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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.