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Finding the Fourth Proportional to 90.12, 134.21 and 86.44

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Solution

The fourth proportional to 90.12, 134.21 and 86.44 is: 128.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.12 : 134.21 = 86.44 : x
  2. Step 2: Convert to fraction form
    90.12/134.21 = 86.44/x
  3. Step 3: Cross multiply
    90.12x = 134.21 × 86.44
  4. Step 4: Simplify right side
    90.12x = 11,601.11
  5. Step 5: Solve for x
    x = 11,601.11/90.12
  6. Step 6: Final answer
    x = 128.73

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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.