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Finding the Fourth Proportional to 86.04, 128.88 and 78.78

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Solution

The fourth proportional to 86.04, 128.88 and 78.78 is: 118.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.04 : 128.88 = 78.78 : x
  2. Step 2: Convert to fraction form
    86.04/128.88 = 78.78/x
  3. Step 3: Cross multiply
    86.04x = 128.88 × 78.78
  4. Step 4: Simplify right side
    86.04x = 10,153.17
  5. Step 5: Solve for x
    x = 10,153.17/86.04
  6. Step 6: Final answer
    x = 118.01

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