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Finding the Fourth Proportional to 80.90, 121.08 and 71.90

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Solution

The fourth proportional to 80.90, 121.08 and 71.90 is: 107.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.90 : 121.08 = 71.90 : x
  2. Step 2: Convert to fraction form
    80.90/121.08 = 71.90/x
  3. Step 3: Cross multiply
    80.90x = 121.08 × 71.90
  4. Step 4: Simplify right side
    80.90x = 8,705.65
  5. Step 5: Solve for x
    x = 8,705.65/80.90
  6. Step 6: Final answer
    x = 107.61

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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.