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Finding the Fourth Proportional to 90.39, 134.67 and 85.95

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Solution

The fourth proportional to 90.39, 134.67 and 85.95 is: 128.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.39 : 134.67 = 85.95 : x
  2. Step 2: Convert to fraction form
    90.39/134.67 = 85.95/x
  3. Step 3: Cross multiply
    90.39x = 134.67 × 85.95
  4. Step 4: Simplify right side
    90.39x = 11,574.73
  5. Step 5: Solve for x
    x = 11,574.73/90.39
  6. Step 6: Final answer
    x = 128.05

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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.