Finding the Fourth Proportional to 100.52, 138.76 and 72.88

Step by Step Solution

1. Step 1: Write the proportion equation
   100.52 : 138.76 = 72.88 : x
2. Step 2: Convert to fraction form
   100.52/138.76 = 72.88/x
3. Step 3: Cross multiply
   100.52x = 138.76 × 72.88
4. Step 4: Simplify right side
   100.52x = 10,112.83
5. Step 5: Solve for x
   x = 10,112.83/100.52
6. Step 6: Final answer
   x = 100.61