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Finding the Fourth Proportional to 812.47, 1,121.39 and 513.53

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Solution

The fourth proportional to 812.47, 1,121.39 and 513.53 is: 708.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.47 : 1,121.39 = 513.53 : x
  2. Step 2: Convert to fraction form
    812.47/1,121.39 = 513.53/x
  3. Step 3: Cross multiply
    812.47x = 1,121.39 × 513.53
  4. Step 4: Simplify right side
    812.47x = 575,866.97
  5. Step 5: Solve for x
    x = 575,866.97/812.47
  6. Step 6: Final answer
    x = 708.78

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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.