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Finding the Fourth Proportional to 86.37, 129.75 and 80.70

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Solution

The fourth proportional to 86.37, 129.75 and 80.70 is: 121.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.37 : 129.75 = 80.70 : x
  2. Step 2: Convert to fraction form
    86.37/129.75 = 80.70/x
  3. Step 3: Cross multiply
    86.37x = 129.75 × 80.70
  4. Step 4: Simplify right side
    86.37x = 10,470.83
  5. Step 5: Solve for x
    x = 10,470.83/86.37
  6. Step 6: Final answer
    x = 121.23

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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.