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Finding the Fourth Proportional to 812.96, 1,121.48 and 781.52

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Solution

The fourth proportional to 812.96, 1,121.48 and 781.52 is: 1,078.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.96 : 1,121.48 = 781.52 : x
  2. Step 2: Convert to fraction form
    812.96/1,121.48 = 781.52/x
  3. Step 3: Cross multiply
    812.96x = 1,121.48 × 781.52
  4. Step 4: Simplify right side
    812.96x = 876,449.53
  5. Step 5: Solve for x
    x = 876,449.53/812.96
  6. Step 6: Final answer
    x = 1,078.10

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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.