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Finding the Fourth Proportional to 310.78, 428.68 and 200.40

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Solution

The fourth proportional to 310.78, 428.68 and 200.40 is: 276.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.78 : 428.68 = 200.40 : x
  2. Step 2: Convert to fraction form
    310.78/428.68 = 200.40/x
  3. Step 3: Cross multiply
    310.78x = 428.68 × 200.40
  4. Step 4: Simplify right side
    310.78x = 85,907.47
  5. Step 5: Solve for x
    x = 85,907.47/310.78
  6. Step 6: Final answer
    x = 276.43

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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.