Finding the Fourth Proportional to 78.96, 118.32 and 72.15

Step by Step Solution

1. Step 1: Write the proportion equation
   78.96 : 118.32 = 72.15 : x
2. Step 2: Convert to fraction form
   78.96/118.32 = 72.15/x
3. Step 3: Cross multiply
   78.96x = 118.32 × 72.15
4. Step 4: Simplify right side
   78.96x = 8,536.79
5. Step 5: Solve for x
   x = 8,536.79/78.96
6. Step 6: Final answer
   x = 108.12