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Finding the Fourth Proportional to 812.78, 1,217.72 and 555.02

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Solution

The fourth proportional to 812.78, 1,217.72 and 555.02 is: 831.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.78 : 1,217.72 = 555.02 : x
  2. Step 2: Convert to fraction form
    812.78/1,217.72 = 555.02/x
  3. Step 3: Cross multiply
    812.78x = 1,217.72 × 555.02
  4. Step 4: Simplify right side
    812.78x = 675,854.25
  5. Step 5: Solve for x
    x = 675,854.25/812.78
  6. Step 6: Final answer
    x = 831.54

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.