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Finding the Fourth Proportional to 91.29, 136.90 and 39.91

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Solution

The fourth proportional to 91.29, 136.90 and 39.91 is: 59.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.29 : 136.90 = 39.91 : x
  2. Step 2: Convert to fraction form
    91.29/136.90 = 39.91/x
  3. Step 3: Cross multiply
    91.29x = 136.90 × 39.91
  4. Step 4: Simplify right side
    91.29x = 5,463.68
  5. Step 5: Solve for x
    x = 5,463.68/91.29
  6. Step 6: Final answer
    x = 59.85

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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.