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Finding the Fourth Proportional to 91.35, 136.22 and 86.49

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Solution

The fourth proportional to 91.35, 136.22 and 86.49 is: 128.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.35 : 136.22 = 86.49 : x
  2. Step 2: Convert to fraction form
    91.35/136.22 = 86.49/x
  3. Step 3: Cross multiply
    91.35x = 136.22 × 86.49
  4. Step 4: Simplify right side
    91.35x = 11,781.24
  5. Step 5: Solve for x
    x = 11,781.24/91.35
  6. Step 6: Final answer
    x = 128.97

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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.