Finding the Fourth Proportional to 100.98, 139.02 and 90.98

Step by Step Solution

1. Step 1: Write the proportion equation
   100.98 : 139.02 = 90.98 : x
2. Step 2: Convert to fraction form
   100.98/139.02 = 90.98/x
3. Step 3: Cross multiply
   100.98x = 139.02 × 90.98
4. Step 4: Simplify right side
   100.98x = 12,647.34
5. Step 5: Solve for x
   x = 12,647.34/100.98
6. Step 6: Final answer
   x = 125.25