Finding the Fourth Proportional to 111.57, 153.78 and 85.25

Step by Step Solution

1. Step 1: Write the proportion equation
   111.57 : 153.78 = 85.25 : x
2. Step 2: Convert to fraction form
   111.57/153.78 = 85.25/x
3. Step 3: Cross multiply
   111.57x = 153.78 × 85.25
4. Step 4: Simplify right side
   111.57x = 13,109.75
5. Step 5: Solve for x
   x = 13,109.75/111.57
6. Step 6: Final answer
   x = 117.50