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Finding the Fourth Proportional to 812.78, 1,217.28 and 629.59

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Solution

The fourth proportional to 812.78, 1,217.28 and 629.59 is: 942.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.78 : 1,217.28 = 629.59 : x
  2. Step 2: Convert to fraction form
    812.78/1,217.28 = 629.59/x
  3. Step 3: Cross multiply
    812.78x = 1,217.28 × 629.59
  4. Step 4: Simplify right side
    812.78x = 766,385.85
  5. Step 5: Solve for x
    x = 766,385.85/812.78
  6. Step 6: Final answer
    x = 942.92

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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.