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Finding the Fourth Proportional to 80.56, 120.85 and 19.70

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Solution

The fourth proportional to 80.56, 120.85 and 19.70 is: 29.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.56 : 120.85 = 19.70 : x
  2. Step 2: Convert to fraction form
    80.56/120.85 = 19.70/x
  3. Step 3: Cross multiply
    80.56x = 120.85 × 19.70
  4. Step 4: Simplify right side
    80.56x = 2,380.29
  5. Step 5: Solve for x
    x = 2,380.29/80.56
  6. Step 6: Final answer
    x = 29.55

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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.