Finding the Fourth Proportional to 99.72, 149.50 and 61.18

Step by Step Solution

1. Step 1: Write the proportion equation
   99.72 : 149.50 = 61.18 : x
2. Step 2: Convert to fraction form
   99.72/149.50 = 61.18/x
3. Step 3: Cross multiply
   99.72x = 149.50 × 61.18
4. Step 4: Simplify right side
   99.72x = 9,146.41
5. Step 5: Solve for x
   x = 9,146.41/99.72
6. Step 6: Final answer
   x = 91.72