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Finding the Fourth Proportional to 90.61, 135.81 and 39.22

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Solution

The fourth proportional to 90.61, 135.81 and 39.22 is: 58.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.61 : 135.81 = 39.22 : x
  2. Step 2: Convert to fraction form
    90.61/135.81 = 39.22/x
  3. Step 3: Cross multiply
    90.61x = 135.81 × 39.22
  4. Step 4: Simplify right side
    90.61x = 5,326.89
  5. Step 5: Solve for x
    x = 5,326.89/90.61
  6. Step 6: Final answer
    x = 58.79

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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.