Finding the Fourth Proportional to 111.32, 153.63 and 78.51

Step by Step Solution

1. Step 1: Write the proportion equation
   111.32 : 153.63 = 78.51 : x
2. Step 2: Convert to fraction form
   111.32/153.63 = 78.51/x
3. Step 3: Cross multiply
   111.32x = 153.63 × 78.51
4. Step 4: Simplify right side
   111.32x = 12,061.49
5. Step 5: Solve for x
   x = 12,061.49/111.32
6. Step 6: Final answer
   x = 108.35