Finding the Fourth Proportional to 78.60, 117.69 and 48.15

Step by Step Solution

1. Step 1: Write the proportion equation
   78.60 : 117.69 = 48.15 : x
2. Step 2: Convert to fraction form
   78.60/117.69 = 48.15/x
3. Step 3: Cross multiply
   78.60x = 117.69 × 48.15
4. Step 4: Simplify right side
   78.60x = 5,666.77
5. Step 5: Solve for x
   x = 5,666.77/78.60
6. Step 6: Final answer
   x = 72.10