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Finding the Fourth Proportional to 80.90, 121.35 and 65.61

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Solution

The fourth proportional to 80.90, 121.35 and 65.61 is: 98.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.90 : 121.35 = 65.61 : x
  2. Step 2: Convert to fraction form
    80.90/121.35 = 65.61/x
  3. Step 3: Cross multiply
    80.90x = 121.35 × 65.61
  4. Step 4: Simplify right side
    80.90x = 7,961.77
  5. Step 5: Solve for x
    x = 7,961.77/80.90
  6. Step 6: Final answer
    x = 98.42

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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.