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Finding the Fourth Proportional to 90.25, 134.51 and 85.12

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Solution

The fourth proportional to 90.25, 134.51 and 85.12 is: 126.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.25 : 134.51 = 85.12 : x
  2. Step 2: Convert to fraction form
    90.25/134.51 = 85.12/x
  3. Step 3: Cross multiply
    90.25x = 134.51 × 85.12
  4. Step 4: Simplify right side
    90.25x = 11,449.87
  5. Step 5: Solve for x
    x = 11,449.87/90.25
  6. Step 6: Final answer
    x = 126.87

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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.