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Finding the Fourth Proportional to 86.94, 130.66 and 81.09

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Solution

The fourth proportional to 86.94, 130.66 and 81.09 is: 121.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.94 : 130.66 = 81.09 : x
  2. Step 2: Convert to fraction form
    86.94/130.66 = 81.09/x
  3. Step 3: Cross multiply
    86.94x = 130.66 × 81.09
  4. Step 4: Simplify right side
    86.94x = 10,595.22
  5. Step 5: Solve for x
    x = 10,595.22/86.94
  6. Step 6: Final answer
    x = 121.87

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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.