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Finding the Fourth Proportional to 90.31, 135.38 and 36.21

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Solution

The fourth proportional to 90.31, 135.38 and 36.21 is: 54.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.31 : 135.38 = 36.21 : x
  2. Step 2: Convert to fraction form
    90.31/135.38 = 36.21/x
  3. Step 3: Cross multiply
    90.31x = 135.38 × 36.21
  4. Step 4: Simplify right side
    90.31x = 4,902.11
  5. Step 5: Solve for x
    x = 4,902.11/90.31
  6. Step 6: Final answer
    x = 54.28

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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.