Finding the Fourth Proportional to 78.78, 117.58 and 73.69

Step by Step Solution

1. Step 1: Write the proportion equation
   78.78 : 117.58 = 73.69 : x
2. Step 2: Convert to fraction form
   78.78/117.58 = 73.69/x
3. Step 3: Cross multiply
   78.78x = 117.58 × 73.69
4. Step 4: Simplify right side
   78.78x = 8,664.10
5. Step 5: Solve for x
   x = 8,664.10/78.78
6. Step 6: Final answer
   x = 109.99