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Finding the Fourth Proportional to 127.72, 177.01 and 121.78

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Solution

The fourth proportional to 127.72, 177.01 and 121.78 is: 168.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.72 : 177.01 = 121.78 : x
  2. Step 2: Convert to fraction form
    127.72/177.01 = 121.78/x
  3. Step 3: Cross multiply
    127.72x = 177.01 × 121.78
  4. Step 4: Simplify right side
    127.72x = 21,555.53
  5. Step 5: Solve for x
    x = 21,555.53/127.72
  6. Step 6: Final answer
    x = 168.78

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.