Finding the Fourth Proportional to 78.10, 107.89 and 72.34

Step by Step Solution

1. Step 1: Write the proportion equation
   78.10 : 107.89 = 72.34 : x
2. Step 2: Convert to fraction form
   78.10/107.89 = 72.34/x
3. Step 3: Cross multiply
   78.10x = 107.89 × 72.34
4. Step 4: Simplify right side
   78.10x = 7,804.76
5. Step 5: Solve for x
   x = 7,804.76/78.10
6. Step 6: Final answer
   x = 99.93