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Finding the Fourth Proportional to 911.70, 1,256.85 and 648.90

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Solution

The fourth proportional to 911.70, 1,256.85 and 648.90 is: 894.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    911.70 : 1,256.85 = 648.90 : x
  2. Step 2: Convert to fraction form
    911.70/1,256.85 = 648.90/x
  3. Step 3: Cross multiply
    911.70x = 1,256.85 × 648.90
  4. Step 4: Simplify right side
    911.70x = 815,569.97
  5. Step 5: Solve for x
    x = 815,569.97/911.70
  6. Step 6: Final answer
    x = 894.56

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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.