Finding the Fourth Proportional to 99.61, 149.31 and 72.47

Step by Step Solution

1. Step 1: Write the proportion equation
   99.61 : 149.31 = 72.47 : x
2. Step 2: Convert to fraction form
   99.61/149.31 = 72.47/x
3. Step 3: Cross multiply
   99.61x = 149.31 × 72.47
4. Step 4: Simplify right side
   99.61x = 10,820.87
5. Step 5: Solve for x
   x = 10,820.87/99.61
6. Step 6: Final answer
   x = 108.64