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Finding the Fourth Proportional to 838.78, 1,260.87 and 812.86

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Solution

The fourth proportional to 838.78, 1,260.87 and 812.86 is: 1,221.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    838.78 : 1,260.87 = 812.86 : x
  2. Step 2: Convert to fraction form
    838.78/1,260.87 = 812.86/x
  3. Step 3: Cross multiply
    838.78x = 1,260.87 × 812.86
  4. Step 4: Simplify right side
    838.78x = 1,024,910.79
  5. Step 5: Solve for x
    x = 1,024,910.79/838.78
  6. Step 6: Final answer
    x = 1,221.91

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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.