Finding the Fourth Proportional to 111.30, 153.50 and 83.72

Step by Step Solution

1. Step 1: Write the proportion equation
   111.30 : 153.50 = 83.72 : x
2. Step 2: Convert to fraction form
   111.30/153.50 = 83.72/x
3. Step 3: Cross multiply
   111.30x = 153.50 × 83.72
4. Step 4: Simplify right side
   111.30x = 12,851.02
5. Step 5: Solve for x
   x = 12,851.02/111.30
6. Step 6: Final answer
   x = 115.46