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Finding the Fourth Proportional to 86.27, 128.81 and 74.57

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Solution

The fourth proportional to 86.27, 128.81 and 74.57 is: 111.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.27 : 128.81 = 74.57 : x
  2. Step 2: Convert to fraction form
    86.27/128.81 = 74.57/x
  3. Step 3: Cross multiply
    86.27x = 128.81 × 74.57
  4. Step 4: Simplify right side
    86.27x = 9,604.34
  5. Step 5: Solve for x
    x = 9,604.34/86.27
  6. Step 6: Final answer
    x = 111.34

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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.