Finding the Fourth Proportional to 100.86, 151.31 and 74.78

Step by Step Solution

1. Step 1: Write the proportion equation
   100.86 : 151.31 = 74.78 : x
2. Step 2: Convert to fraction form
   100.86/151.31 = 74.78/x
3. Step 3: Cross multiply
   100.86x = 151.31 × 74.78
4. Step 4: Simplify right side
   100.86x = 11,313.83
5. Step 5: Solve for x
   x = 11,313.83/100.86
6. Step 6: Final answer
   x = 112.17