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Finding the Fourth Proportional to 80.76, 111.20 and 77.28

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Solution

The fourth proportional to 80.76, 111.20 and 77.28 is: 106.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.76 : 111.20 = 77.28 : x
  2. Step 2: Convert to fraction form
    80.76/111.20 = 77.28/x
  3. Step 3: Cross multiply
    80.76x = 111.20 × 77.28
  4. Step 4: Simplify right side
    80.76x = 8,593.54
  5. Step 5: Solve for x
    x = 8,593.54/80.76
  6. Step 6: Final answer
    x = 106.41

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Find fourth proportional to 40.38, 55.60 and 38.64
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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.