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Finding the Fourth Proportional to 778.09, 1,073.79 and 428.78

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Solution

The fourth proportional to 778.09, 1,073.79 and 428.78 is: 591.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.09 : 1,073.79 = 428.78 : x
  2. Step 2: Convert to fraction form
    778.09/1,073.79 = 428.78/x
  3. Step 3: Cross multiply
    778.09x = 1,073.79 × 428.78
  4. Step 4: Simplify right side
    778.09x = 460,419.68
  5. Step 5: Solve for x
    x = 460,419.68/778.09
  6. Step 6: Final answer
    x = 591.73

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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.