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Finding the Fourth Proportional to 91.63, 138.06 and 81.81

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Solution

The fourth proportional to 91.63, 138.06 and 81.81 is: 123.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.63 : 138.06 = 81.81 : x
  2. Step 2: Convert to fraction form
    91.63/138.06 = 81.81/x
  3. Step 3: Cross multiply
    91.63x = 138.06 × 81.81
  4. Step 4: Simplify right side
    91.63x = 11,294.00
  5. Step 5: Solve for x
    x = 11,294.00/91.63
  6. Step 6: Final answer
    x = 123.26

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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.