Finding the Fourth Proportional to 139.98, 193.18 and 90.86

Step by Step Solution

1. Step 1: Write the proportion equation
   139.98 : 193.18 = 90.86 : x
2. Step 2: Convert to fraction form
   139.98/193.18 = 90.86/x
3. Step 3: Cross multiply
   139.98x = 193.18 × 90.86
4. Step 4: Simplify right side
   139.98x = 17,552.33
5. Step 5: Solve for x
   x = 17,552.33/139.98
6. Step 6: Final answer
   x = 125.39