Finding the Fourth Proportional to 99.79, 149.72 and 31.31

Step by Step Solution

1. Step 1: Write the proportion equation
   99.79 : 149.72 = 31.31 : x
2. Step 2: Convert to fraction form
   99.79/149.72 = 31.31/x
3. Step 3: Cross multiply
   99.79x = 149.72 × 31.31
4. Step 4: Simplify right side
   99.79x = 4,687.73
5. Step 5: Solve for x
   x = 4,687.73/99.79
6. Step 6: Final answer
   x = 46.98