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Finding the Fourth Proportional to 821.22, 1,133.22 and 489.72

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Solution

The fourth proportional to 821.22, 1,133.22 and 489.72 is: 675.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.22 : 1,133.22 = 489.72 : x
  2. Step 2: Convert to fraction form
    821.22/1,133.22 = 489.72/x
  3. Step 3: Cross multiply
    821.22x = 1,133.22 × 489.72
  4. Step 4: Simplify right side
    821.22x = 554,960.50
  5. Step 5: Solve for x
    x = 554,960.50/821.22
  6. Step 6: Final answer
    x = 675.78

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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.