Finding the Fourth Proportional to 123.50, 185.31 and 99.50

Step by Step Solution

1. Step 1: Write the proportion equation
   123.50 : 185.31 = 99.50 : x
2. Step 2: Convert to fraction form
   123.50/185.31 = 99.50/x
3. Step 3: Cross multiply
   123.50x = 185.31 × 99.50
4. Step 4: Simplify right side
   123.50x = 18,438.35
5. Step 5: Solve for x
   x = 18,438.35/123.50
6. Step 6: Final answer
   x = 149.30