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Finding the Fourth Proportional to 842.76, 1,257.76 and 820.88

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Solution

The fourth proportional to 842.76, 1,257.76 and 820.88 is: 1,225.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.76 : 1,257.76 = 820.88 : x
  2. Step 2: Convert to fraction form
    842.76/1,257.76 = 820.88/x
  3. Step 3: Cross multiply
    842.76x = 1,257.76 × 820.88
  4. Step 4: Simplify right side
    842.76x = 1,032,470.03
  5. Step 5: Solve for x
    x = 1,032,470.03/842.76
  6. Step 6: Final answer
    x = 1,225.11

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.