Finding the Fourth Proportional to 104.72, 156.78 and 72.15

Step by Step Solution

1. Step 1: Write the proportion equation
   104.72 : 156.78 = 72.15 : x
2. Step 2: Convert to fraction form
   104.72/156.78 = 72.15/x
3. Step 3: Cross multiply
   104.72x = 156.78 × 72.15
4. Step 4: Simplify right side
   104.72x = 11,311.68
5. Step 5: Solve for x
   x = 11,311.68/104.72
6. Step 6: Final answer
   x = 108.02