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Finding the Fourth Proportional to 86.37, 128.92 and 80.02

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Solution

The fourth proportional to 86.37, 128.92 and 80.02 is: 119.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.37 : 128.92 = 80.02 : x
  2. Step 2: Convert to fraction form
    86.37/128.92 = 80.02/x
  3. Step 3: Cross multiply
    86.37x = 128.92 × 80.02
  4. Step 4: Simplify right side
    86.37x = 10,316.18
  5. Step 5: Solve for x
    x = 10,316.18/86.37
  6. Step 6: Final answer
    x = 119.44

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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.