Finding the Fourth Proportional to 139.05, 191.84 and 89.91

Step by Step Solution

1. Step 1: Write the proportion equation
   139.05 : 191.84 = 89.91 : x
2. Step 2: Convert to fraction form
   139.05/191.84 = 89.91/x
3. Step 3: Cross multiply
   139.05x = 191.84 × 89.91
4. Step 4: Simplify right side
   139.05x = 17,248.33
5. Step 5: Solve for x
   x = 17,248.33/139.05
6. Step 6: Final answer
   x = 124.04