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Finding the Fourth Proportional to 90.75, 135.92 and 69.05

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Solution

The fourth proportional to 90.75, 135.92 and 69.05 is: 103.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.75 : 135.92 = 69.05 : x
  2. Step 2: Convert to fraction form
    90.75/135.92 = 69.05/x
  3. Step 3: Cross multiply
    90.75x = 135.92 × 69.05
  4. Step 4: Simplify right side
    90.75x = 9,384.60
  5. Step 5: Solve for x
    x = 9,384.60/90.75
  6. Step 6: Final answer
    x = 103.41

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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.