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Finding the Fourth Proportional to 121.28, 181.98 and 80.78

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Solution

The fourth proportional to 121.28, 181.98 and 80.78 is: 121.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.28 : 181.98 = 80.78 : x
  2. Step 2: Convert to fraction form
    121.28/181.98 = 80.78/x
  3. Step 3: Cross multiply
    121.28x = 181.98 × 80.78
  4. Step 4: Simplify right side
    121.28x = 14,700.34
  5. Step 5: Solve for x
    x = 14,700.34/121.28
  6. Step 6: Final answer
    x = 121.21

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