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Finding the Fourth Proportional to 680.78, 939.71 and 418.95

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Solution

The fourth proportional to 680.78, 939.71 and 418.95 is: 578.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.78 : 939.71 = 418.95 : x
  2. Step 2: Convert to fraction form
    680.78/939.71 = 418.95/x
  3. Step 3: Cross multiply
    680.78x = 939.71 × 418.95
  4. Step 4: Simplify right side
    680.78x = 393,692.55
  5. Step 5: Solve for x
    x = 393,692.55/680.78
  6. Step 6: Final answer
    x = 578.29

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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.