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Finding the Fourth Proportional to 80.74, 120.30 and 77.25

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Solution

The fourth proportional to 80.74, 120.30 and 77.25 is: 115.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.74 : 120.30 = 77.25 : x
  2. Step 2: Convert to fraction form
    80.74/120.30 = 77.25/x
  3. Step 3: Cross multiply
    80.74x = 120.30 × 77.25
  4. Step 4: Simplify right side
    80.74x = 9,293.18
  5. Step 5: Solve for x
    x = 9,293.18/80.74
  6. Step 6: Final answer
    x = 115.10

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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.