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Finding the Fourth Proportional to 778.12, 1,073.80 and 428.80

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Solution

The fourth proportional to 778.12, 1,073.80 and 428.80 is: 591.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.12 : 1,073.80 = 428.80 : x
  2. Step 2: Convert to fraction form
    778.12/1,073.80 = 428.80/x
  3. Step 3: Cross multiply
    778.12x = 1,073.80 × 428.80
  4. Step 4: Simplify right side
    778.12x = 460,445.44
  5. Step 5: Solve for x
    x = 460,445.44/778.12
  6. Step 6: Final answer
    x = 591.74

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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.