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Finding the Fourth Proportional to 90.69, 135.90 and 39.29

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Solution

The fourth proportional to 90.69, 135.90 and 39.29 is: 58.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.69 : 135.90 = 39.29 : x
  2. Step 2: Convert to fraction form
    90.69/135.90 = 39.29/x
  3. Step 3: Cross multiply
    90.69x = 135.90 × 39.29
  4. Step 4: Simplify right side
    90.69x = 5,338.83
  5. Step 5: Solve for x
    x = 5,338.83/90.69
  6. Step 6: Final answer
    x = 58.87

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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.