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Finding the Fourth Proportional to 90.30, 135.09 and 85.50

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Solution

The fourth proportional to 90.30, 135.09 and 85.50 is: 127.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.30 : 135.09 = 85.50 : x
  2. Step 2: Convert to fraction form
    90.30/135.09 = 85.50/x
  3. Step 3: Cross multiply
    90.30x = 135.09 × 85.50
  4. Step 4: Simplify right side
    90.30x = 11,550.20
  5. Step 5: Solve for x
    x = 11,550.20/90.30
  6. Step 6: Final answer
    x = 127.91

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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.