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Finding the Fourth Proportional to 820.88, 1,229.88 and 387.44

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Solution

The fourth proportional to 820.88, 1,229.88 and 387.44 is: 580.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.88 : 1,229.88 = 387.44 : x
  2. Step 2: Convert to fraction form
    820.88/1,229.88 = 387.44/x
  3. Step 3: Cross multiply
    820.88x = 1,229.88 × 387.44
  4. Step 4: Simplify right side
    820.88x = 476,504.71
  5. Step 5: Solve for x
    x = 476,504.71/820.88
  6. Step 6: Final answer
    x = 580.48

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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.