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Finding the Fourth Proportional to 91.25, 136.77 and 86.19

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Solution

The fourth proportional to 91.25, 136.77 and 86.19 is: 129.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.25 : 136.77 = 86.19 : x
  2. Step 2: Convert to fraction form
    91.25/136.77 = 86.19/x
  3. Step 3: Cross multiply
    91.25x = 136.77 × 86.19
  4. Step 4: Simplify right side
    91.25x = 11,788.21
  5. Step 5: Solve for x
    x = 11,788.21/91.25
  6. Step 6: Final answer
    x = 129.19

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.