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Finding the Fourth Proportional to 80.89, 121.30 and 61.75

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Solution

The fourth proportional to 80.89, 121.30 and 61.75 is: 92.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.89 : 121.30 = 61.75 : x
  2. Step 2: Convert to fraction form
    80.89/121.30 = 61.75/x
  3. Step 3: Cross multiply
    80.89x = 121.30 × 61.75
  4. Step 4: Simplify right side
    80.89x = 7,489.82
  5. Step 5: Solve for x
    x = 7,489.82/80.89
  6. Step 6: Final answer
    x = 92.60

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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.