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Finding the Fourth Proportional to 91.50, 136.43 and 81.25

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Solution

The fourth proportional to 91.50, 136.43 and 81.25 is: 121.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.50 : 136.43 = 81.25 : x
  2. Step 2: Convert to fraction form
    91.50/136.43 = 81.25/x
  3. Step 3: Cross multiply
    91.50x = 136.43 × 81.25
  4. Step 4: Simplify right side
    91.50x = 11,084.49
  5. Step 5: Solve for x
    x = 11,084.49/91.50
  6. Step 6: Final answer
    x = 121.15

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.