Finding the Fourth Proportional to 78.22, 116.69 and 72.15

Step by Step Solution

1. Step 1: Write the proportion equation
   78.22 : 116.69 = 72.15 : x
2. Step 2: Convert to fraction form
   78.22/116.69 = 72.15/x
3. Step 3: Cross multiply
   78.22x = 116.69 × 72.15
4. Step 4: Simplify right side
   78.22x = 8,419.18
5. Step 5: Solve for x
   x = 8,419.18/78.22
6. Step 6: Final answer
   x = 107.63