Finding the Fourth Proportional to 106.78, 147.32 and 72.28

Step by Step Solution

1. Step 1: Write the proportion equation
   106.78 : 147.32 = 72.28 : x
2. Step 2: Convert to fraction form
   106.78/147.32 = 72.28/x
3. Step 3: Cross multiply
   106.78x = 147.32 × 72.28
4. Step 4: Simplify right side
   106.78x = 10,648.29
5. Step 5: Solve for x
   x = 10,648.29/106.78
6. Step 6: Final answer
   x = 99.72