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Finding the Fourth Proportional to 91.08, 137.31 and 81.06

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Solution

The fourth proportional to 91.08, 137.31 and 81.06 is: 122.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.08 : 137.31 = 81.06 : x
  2. Step 2: Convert to fraction form
    91.08/137.31 = 81.06/x
  3. Step 3: Cross multiply
    91.08x = 137.31 × 81.06
  4. Step 4: Simplify right side
    91.08x = 11,130.35
  5. Step 5: Solve for x
    x = 11,130.35/91.08
  6. Step 6: Final answer
    x = 122.20

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.