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Finding the Fourth Proportional to 90.81, 136.31 and 67.91

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Solution

The fourth proportional to 90.81, 136.31 and 67.91 is: 101.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.81 : 136.31 = 67.91 : x
  2. Step 2: Convert to fraction form
    90.81/136.31 = 67.91/x
  3. Step 3: Cross multiply
    90.81x = 136.31 × 67.91
  4. Step 4: Simplify right side
    90.81x = 9,255.79
  5. Step 5: Solve for x
    x = 9,255.79/90.81
  6. Step 6: Final answer
    x = 101.92

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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.