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Finding the Fourth Proportional to 781.76, 1,077.96 and 641.44

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Solution

The fourth proportional to 781.76, 1,077.96 and 641.44 is: 884.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.76 : 1,077.96 = 641.44 : x
  2. Step 2: Convert to fraction form
    781.76/1,077.96 = 641.44/x
  3. Step 3: Cross multiply
    781.76x = 1,077.96 × 641.44
  4. Step 4: Simplify right side
    781.76x = 691,446.66
  5. Step 5: Solve for x
    x = 691,446.66/781.76
  6. Step 6: Final answer
    x = 884.47

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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.