Finding the Fourth Proportional to 111.50, 153.87 and 65.50

Step by Step Solution

1. Step 1: Write the proportion equation
   111.50 : 153.87 = 65.50 : x
2. Step 2: Convert to fraction form
   111.50/153.87 = 65.50/x
3. Step 3: Cross multiply
   111.50x = 153.87 × 65.50
4. Step 4: Simplify right side
   111.50x = 10,078.49
5. Step 5: Solve for x
   x = 10,078.49/111.50
6. Step 6: Final answer
   x = 90.39