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Finding the Fourth Proportional to 87, 129.82 and 78.92

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Solution

The fourth proportional to 87, 129.82 and 78.92 is: 117.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    87 : 129.82 = 78.92 : x
  2. Step 2: Convert to fraction form
    87/129.82 = 78.92/x
  3. Step 3: Cross multiply
    87x = 129.82 × 78.92
  4. Step 4: Simplify right side
    87x = 10,245.39
  5. Step 5: Solve for x
    x = 10,245.39/87
  6. Step 6: Final answer
    x = 117.76

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