Finding the Fourth Proportional to 107.16, 147.72 and 72.12

Step by Step Solution

1. Step 1: Write the proportion equation
   107.16 : 147.72 = 72.12 : x
2. Step 2: Convert to fraction form
   107.16/147.72 = 72.12/x
3. Step 3: Cross multiply
   107.16x = 147.72 × 72.12
4. Step 4: Simplify right side
   107.16x = 10,653.57
5. Step 5: Solve for x
   x = 10,653.57/107.16
6. Step 6: Final answer
   x = 99.42