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Finding the Fourth Proportional to 86.87, 130.40 and 80.49

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Solution

The fourth proportional to 86.87, 130.40 and 80.49 is: 120.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.87 : 130.40 = 80.49 : x
  2. Step 2: Convert to fraction form
    86.87/130.40 = 80.49/x
  3. Step 3: Cross multiply
    86.87x = 130.40 × 80.49
  4. Step 4: Simplify right side
    86.87x = 10,496.10
  5. Step 5: Solve for x
    x = 10,496.10/86.87
  6. Step 6: Final answer
    x = 120.82

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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.