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Finding the Fourth Proportional to 86.33, 128.76 and 80.66

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Solution

The fourth proportional to 86.33, 128.76 and 80.66 is: 120.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.33 : 128.76 = 80.66 : x
  2. Step 2: Convert to fraction form
    86.33/128.76 = 80.66/x
  3. Step 3: Cross multiply
    86.33x = 128.76 × 80.66
  4. Step 4: Simplify right side
    86.33x = 10,385.14
  5. Step 5: Solve for x
    x = 10,385.14/86.33
  6. Step 6: Final answer
    x = 120.30

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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.