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Finding the Fourth Proportional to 81.28, 112.64 and 80.24

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Solution

The fourth proportional to 81.28, 112.64 and 80.24 is: 111.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.28 : 112.64 = 80.24 : x
  2. Step 2: Convert to fraction form
    81.28/112.64 = 80.24/x
  3. Step 3: Cross multiply
    81.28x = 112.64 × 80.24
  4. Step 4: Simplify right side
    81.28x = 9,038.23
  5. Step 5: Solve for x
    x = 9,038.23/81.28
  6. Step 6: Final answer
    x = 111.20

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.