Finding the Fourth Proportional to 78.50, 117.79 and 72.69

Step by Step Solution

1. Step 1: Write the proportion equation
   78.50 : 117.79 = 72.69 : x
2. Step 2: Convert to fraction form
   78.50/117.79 = 72.69/x
3. Step 3: Cross multiply
   78.50x = 117.79 × 72.69
4. Step 4: Simplify right side
   78.50x = 8,562.16
5. Step 5: Solve for x
   x = 8,562.16/78.50
6. Step 6: Final answer
   x = 109.07