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Finding the Fourth Proportional to 80.56, 120.20 and 78.16

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Solution

The fourth proportional to 80.56, 120.20 and 78.16 is: 116.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.56 : 120.20 = 78.16 : x
  2. Step 2: Convert to fraction form
    80.56/120.20 = 78.16/x
  3. Step 3: Cross multiply
    80.56x = 120.20 × 78.16
  4. Step 4: Simplify right side
    80.56x = 9,394.83
  5. Step 5: Solve for x
    x = 9,394.83/80.56
  6. Step 6: Final answer
    x = 116.62

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.