Finding the Fourth Proportional to 139.31, 192.18 and 89.51

Step by Step Solution

1. Step 1: Write the proportion equation
   139.31 : 192.18 = 89.51 : x
2. Step 2: Convert to fraction form
   139.31/192.18 = 89.51/x
3. Step 3: Cross multiply
   139.31x = 192.18 × 89.51
4. Step 4: Simplify right side
   139.31x = 17,201.07
5. Step 5: Solve for x
   x = 17,201.07/139.31
6. Step 6: Final answer
   x = 123.48