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Finding the Fourth Proportional to 86.27, 128.64 and 76.73

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Solution

The fourth proportional to 86.27, 128.64 and 76.73 is: 114.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.27 : 128.64 = 76.73 : x
  2. Step 2: Convert to fraction form
    86.27/128.64 = 76.73/x
  3. Step 3: Cross multiply
    86.27x = 128.64 × 76.73
  4. Step 4: Simplify right side
    86.27x = 9,870.16
  5. Step 5: Solve for x
    x = 9,870.16/86.27
  6. Step 6: Final answer
    x = 114.41

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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.