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Finding the Fourth Proportional to 86.34, 128.87 and 80.32

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Solution

The fourth proportional to 86.34, 128.87 and 80.32 is: 119.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.34 : 128.87 = 80.32 : x
  2. Step 2: Convert to fraction form
    86.34/128.87 = 80.32/x
  3. Step 3: Cross multiply
    86.34x = 128.87 × 80.32
  4. Step 4: Simplify right side
    86.34x = 10,350.84
  5. Step 5: Solve for x
    x = 10,350.84/86.34
  6. Step 6: Final answer
    x = 119.88

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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.