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Finding the Fourth Proportional to 90.80, 135.54 and 80

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Solution

The fourth proportional to 90.80, 135.54 and 80 is: 119.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.80 : 135.54 = 80 : x
  2. Step 2: Convert to fraction form
    90.80/135.54 = 80/x
  3. Step 3: Cross multiply
    90.80x = 135.54 × 80
  4. Step 4: Simplify right side
    90.80x = 10,843.20
  5. Step 5: Solve for x
    x = 10,843.20/90.80
  6. Step 6: Final answer
    x = 119.42

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.