Finding the Fourth Proportional to 99.96, 137.79 and 78.09

Step by Step Solution

1. Step 1: Write the proportion equation
   99.96 : 137.79 = 78.09 : x
2. Step 2: Convert to fraction form
   99.96/137.79 = 78.09/x
3. Step 3: Cross multiply
   99.96x = 137.79 × 78.09
4. Step 4: Simplify right side
   99.96x = 10,760.02
5. Step 5: Solve for x
   x = 10,760.02/99.96
6. Step 6: Final answer
   x = 107.64