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Finding the Fourth Proportional to 86.87, 129.20 and 86.06

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Solution

The fourth proportional to 86.87, 129.20 and 86.06 is: 127.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.87 : 129.20 = 86.06 : x
  2. Step 2: Convert to fraction form
    86.87/129.20 = 86.06/x
  3. Step 3: Cross multiply
    86.87x = 129.20 × 86.06
  4. Step 4: Simplify right side
    86.87x = 11,118.84
  5. Step 5: Solve for x
    x = 11,118.84/86.87
  6. Step 6: Final answer
    x = 127.99

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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.