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Finding the Fourth Proportional to 680.50, 939.15 and 385.78

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Solution

The fourth proportional to 680.50, 939.15 and 385.78 is: 532.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.50 : 939.15 = 385.78 : x
  2. Step 2: Convert to fraction form
    680.50/939.15 = 385.78/x
  3. Step 3: Cross multiply
    680.50x = 939.15 × 385.78
  4. Step 4: Simplify right side
    680.50x = 362,305.29
  5. Step 5: Solve for x
    x = 362,305.29/680.50
  6. Step 6: Final answer
    x = 532.41

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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.