Finding the Fourth Proportional to 111.57, 153.99 and 78.84

Step by Step Solution

1. Step 1: Write the proportion equation
   111.57 : 153.99 = 78.84 : x
2. Step 2: Convert to fraction form
   111.57/153.99 = 78.84/x
3. Step 3: Cross multiply
   111.57x = 153.99 × 78.84
4. Step 4: Simplify right side
   111.57x = 12,140.57
5. Step 5: Solve for x
   x = 12,140.57/111.57
6. Step 6: Final answer
   x = 108.82