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Finding the Fourth Proportional to 90.09, 135.18 and 38.79

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Solution

The fourth proportional to 90.09, 135.18 and 38.79 is: 58.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.09 : 135.18 = 38.79 : x
  2. Step 2: Convert to fraction form
    90.09/135.18 = 38.79/x
  3. Step 3: Cross multiply
    90.09x = 135.18 × 38.79
  4. Step 4: Simplify right side
    90.09x = 5,243.63
  5. Step 5: Solve for x
    x = 5,243.63/90.09
  6. Step 6: Final answer
    x = 58.20

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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.