Finding the Fourth Proportional to 109.17, 150.50 and 78.09

Step by Step Solution

1. Step 1: Write the proportion equation
   109.17 : 150.50 = 78.09 : x
2. Step 2: Convert to fraction form
   109.17/150.50 = 78.09/x
3. Step 3: Cross multiply
   109.17x = 150.50 × 78.09
4. Step 4: Simplify right side
   109.17x = 11,752.15
5. Step 5: Solve for x
   x = 11,752.15/109.17
6. Step 6: Final answer
   x = 107.65