Finding the Fourth Proportional to 111.00, 166.15 and 80.43

Step by Step Solution

1. Step 1: Write the proportion equation
   111.00 : 166.15 = 80.43 : x
2. Step 2: Convert to fraction form
   111.00/166.15 = 80.43/x
3. Step 3: Cross multiply
   111.00x = 166.15 × 80.43
4. Step 4: Simplify right side
   111.00x = 13,362.92
5. Step 5: Solve for x
   x = 13,362.92/111.00
6. Step 6: Final answer
   x = 120.38