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Finding the Fourth Proportional to 86.07, 128.88 and 69.66

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Solution

The fourth proportional to 86.07, 128.88 and 69.66 is: 104.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.07 : 128.88 = 69.66 : x
  2. Step 2: Convert to fraction form
    86.07/128.88 = 69.66/x
  3. Step 3: Cross multiply
    86.07x = 128.88 × 69.66
  4. Step 4: Simplify right side
    86.07x = 8,977.78
  5. Step 5: Solve for x
    x = 8,977.78/86.07
  6. Step 6: Final answer
    x = 104.31

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.