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Finding the Fourth Proportional to 86.49, 129.11 and 80.15

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Solution

The fourth proportional to 86.49, 129.11 and 80.15 is: 119.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.49 : 129.11 = 80.15 : x
  2. Step 2: Convert to fraction form
    86.49/129.11 = 80.15/x
  3. Step 3: Cross multiply
    86.49x = 129.11 × 80.15
  4. Step 4: Simplify right side
    86.49x = 10,347.12
  5. Step 5: Solve for x
    x = 10,347.12/86.49
  6. Step 6: Final answer
    x = 119.63

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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.