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Finding the Fourth Proportional to 106.80, 159.95 and 81.09

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Solution

The fourth proportional to 106.80, 159.95 and 81.09 is: 121.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    106.80 : 159.95 = 81.09 : x
  2. Step 2: Convert to fraction form
    106.80/159.95 = 81.09/x
  3. Step 3: Cross multiply
    106.80x = 159.95 × 81.09
  4. Step 4: Simplify right side
    106.80x = 12,969.94
  5. Step 5: Solve for x
    x = 12,969.94/106.80
  6. Step 6: Final answer
    x = 121.44

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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.