Finding the Fourth Proportional to 111.15, 166.05 and 99.72

Step by Step Solution

1. Step 1: Write the proportion equation
   111.15 : 166.05 = 99.72 : x
2. Step 2: Convert to fraction form
   111.15/166.05 = 99.72/x
3. Step 3: Cross multiply
   111.15x = 166.05 × 99.72
4. Step 4: Simplify right side
   111.15x = 16,558.51
5. Step 5: Solve for x
   x = 16,558.51/111.15
6. Step 6: Final answer
   x = 148.97