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Finding the Fourth Proportional to 638.42, 956.78 and 272.76

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Solution

The fourth proportional to 638.42, 956.78 and 272.76 is: 408.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.42 : 956.78 = 272.76 : x
  2. Step 2: Convert to fraction form
    638.42/956.78 = 272.76/x
  3. Step 3: Cross multiply
    638.42x = 956.78 × 272.76
  4. Step 4: Simplify right side
    638.42x = 260,971.31
  5. Step 5: Solve for x
    x = 260,971.31/638.42
  6. Step 6: Final answer
    x = 408.78

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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.