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Finding the Fourth Proportional to 90.36, 135.78 and 54.32

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Solution

The fourth proportional to 90.36, 135.78 and 54.32 is: 81.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.36 : 135.78 = 54.32 : x
  2. Step 2: Convert to fraction form
    90.36/135.78 = 54.32/x
  3. Step 3: Cross multiply
    90.36x = 135.78 × 54.32
  4. Step 4: Simplify right side
    90.36x = 7,375.57
  5. Step 5: Solve for x
    x = 7,375.57/90.36
  6. Step 6: Final answer
    x = 81.62

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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.