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Finding the Fourth Proportional to 254.49, 381.71 and 81.15

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Solution

The fourth proportional to 254.49, 381.71 and 81.15 is: 121.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    254.49 : 381.71 = 81.15 : x
  2. Step 2: Convert to fraction form
    254.49/381.71 = 81.15/x
  3. Step 3: Cross multiply
    254.49x = 381.71 × 81.15
  4. Step 4: Simplify right side
    254.49x = 30,975.36
  5. Step 5: Solve for x
    x = 30,975.36/254.49
  6. Step 6: Final answer
    x = 121.72

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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.