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Finding the Fourth Proportional to 515.49, 772.21 and 428.55

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Solution

The fourth proportional to 515.49, 772.21 and 428.55 is: 641.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.49 : 772.21 = 428.55 : x
  2. Step 2: Convert to fraction form
    515.49/772.21 = 428.55/x
  3. Step 3: Cross multiply
    515.49x = 772.21 × 428.55
  4. Step 4: Simplify right side
    515.49x = 330,930.60
  5. Step 5: Solve for x
    x = 330,930.60/515.49
  6. Step 6: Final answer
    x = 641.97

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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.