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Finding the Fourth Proportional to 91.21, 125.85 and 86.59

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Solution

The fourth proportional to 91.21, 125.85 and 86.59 is: 119.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.21 : 125.85 = 86.59 : x
  2. Step 2: Convert to fraction form
    91.21/125.85 = 86.59/x
  3. Step 3: Cross multiply
    91.21x = 125.85 × 86.59
  4. Step 4: Simplify right side
    91.21x = 10,897.70
  5. Step 5: Solve for x
    x = 10,897.70/91.21
  6. Step 6: Final answer
    x = 119.48

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.