Finding the Fourth Proportional to 93.72, 129.34 and 78.15

Step by Step Solution

1. Step 1: Write the proportion equation
   93.72 : 129.34 = 78.15 : x
2. Step 2: Convert to fraction form
   93.72/129.34 = 78.15/x
3. Step 3: Cross multiply
   93.72x = 129.34 × 78.15
4. Step 4: Simplify right side
   93.72x = 10,107.73
5. Step 5: Solve for x
   x = 10,107.73/93.72
6. Step 6: Final answer
   x = 107.85