Finding the Fourth Proportional to 78.68, 117.89 and 48.15

Step by Step Solution

1. Step 1: Write the proportion equation
   78.68 : 117.89 = 48.15 : x
2. Step 2: Convert to fraction form
   78.68/117.89 = 48.15/x
3. Step 3: Cross multiply
   78.68x = 117.89 × 48.15
4. Step 4: Simplify right side
   78.68x = 5,676.28
5. Step 5: Solve for x
   x = 5,676.28/78.68
6. Step 6: Final answer
   x = 72.15