Finding the Fourth Proportional to 139.29, 192.16 and 90.18

Step by Step Solution

1. Step 1: Write the proportion equation
   139.29 : 192.16 = 90.18 : x
2. Step 2: Convert to fraction form
   139.29/192.16 = 90.18/x
3. Step 3: Cross multiply
   139.29x = 192.16 × 90.18
4. Step 4: Simplify right side
   139.29x = 17,329.02
5. Step 5: Solve for x
   x = 17,329.02/139.29
6. Step 6: Final answer
   x = 124.41