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Finding the Fourth Proportional to 91.78, 127.56 and 90.82

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Solution

The fourth proportional to 91.78, 127.56 and 90.82 is: 126.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.78 : 127.56 = 90.82 : x
  2. Step 2: Convert to fraction form
    91.78/127.56 = 90.82/x
  3. Step 3: Cross multiply
    91.78x = 127.56 × 90.82
  4. Step 4: Simplify right side
    91.78x = 11,584.55
  5. Step 5: Solve for x
    x = 11,584.55/91.78
  6. Step 6: Final answer
    x = 126.22

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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.