Finding the Fourth Proportional to 78.84, 108.09 and 72.81

Step by Step Solution

1. Step 1: Write the proportion equation
   78.84 : 108.09 = 72.81 : x
2. Step 2: Convert to fraction form
   78.84/108.09 = 72.81/x
3. Step 3: Cross multiply
   78.84x = 108.09 × 72.81
4. Step 4: Simplify right side
   78.84x = 7,870.03
5. Step 5: Solve for x
   x = 7,870.03/78.84
6. Step 6: Final answer
   x = 99.82