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Finding the Fourth Proportional to 86.22, 128.69 and 75.97

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Solution

The fourth proportional to 86.22, 128.69 and 75.97 is: 113.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.22 : 128.69 = 75.97 : x
  2. Step 2: Convert to fraction form
    86.22/128.69 = 75.97/x
  3. Step 3: Cross multiply
    86.22x = 128.69 × 75.97
  4. Step 4: Simplify right side
    86.22x = 9,776.65
  5. Step 5: Solve for x
    x = 9,776.65/86.22
  6. Step 6: Final answer
    x = 113.39

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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.