Finding the Fourth Proportional to 137.98, 190.38 and 100.72

Step by Step Solution

1. Step 1: Write the proportion equation
   137.98 : 190.38 = 100.72 : x
2. Step 2: Convert to fraction form
   137.98/190.38 = 100.72/x
3. Step 3: Cross multiply
   137.98x = 190.38 × 100.72
4. Step 4: Simplify right side
   137.98x = 19,175.07
5. Step 5: Solve for x
   x = 19,175.07/137.98
6. Step 6: Final answer
   x = 138.97