Finding the Fourth Proportional to 72.91, 100.61 and 40.16

Step by Step Solution

1. Step 1: Write the proportion equation
   72.91 : 100.61 = 40.16 : x
2. Step 2: Convert to fraction form
   72.91/100.61 = 40.16/x
3. Step 3: Cross multiply
   72.91x = 100.61 × 40.16
4. Step 4: Simplify right side
   72.91x = 4,039.79
5. Step 5: Solve for x
   x = 4,039.79/72.91
6. Step 6: Final answer
   x = 55.41