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Finding the Fourth Proportional to 90.32, 135.30 and 85.56

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Solution

The fourth proportional to 90.32, 135.30 and 85.56 is: 128.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.32 : 135.30 = 85.56 : x
  2. Step 2: Convert to fraction form
    90.32/135.30 = 85.56/x
  3. Step 3: Cross multiply
    90.32x = 135.30 × 85.56
  4. Step 4: Simplify right side
    90.32x = 11,576.27
  5. Step 5: Solve for x
    x = 11,576.27/90.32
  6. Step 6: Final answer
    x = 128.17

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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.