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Finding the Fourth Proportional to 90.76, 135.84 and 68.96

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Solution

The fourth proportional to 90.76, 135.84 and 68.96 is: 103.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.76 : 135.84 = 68.96 : x
  2. Step 2: Convert to fraction form
    90.76/135.84 = 68.96/x
  3. Step 3: Cross multiply
    90.76x = 135.84 × 68.96
  4. Step 4: Simplify right side
    90.76x = 9,367.53
  5. Step 5: Solve for x
    x = 9,367.53/90.76
  6. Step 6: Final answer
    x = 103.21

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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.