Finding the Fourth Proportional to 101.88, 139.63 and 100.72

Step by Step Solution

1. Step 1: Write the proportion equation
   101.88 : 139.63 = 100.72 : x
2. Step 2: Convert to fraction form
   101.88/139.63 = 100.72/x
3. Step 3: Cross multiply
   101.88x = 139.63 × 100.72
4. Step 4: Simplify right side
   101.88x = 14,063.53
5. Step 5: Solve for x
   x = 14,063.53/101.88
6. Step 6: Final answer
   x = 138.04