Finding the Fourth Proportional to 100.05, 137.54 and 90.15

Step by Step Solution

1. Step 1: Write the proportion equation
   100.05 : 137.54 = 90.15 : x
2. Step 2: Convert to fraction form
   100.05/137.54 = 90.15/x
3. Step 3: Cross multiply
   100.05x = 137.54 × 90.15
4. Step 4: Simplify right side
   100.05x = 12,398.78
5. Step 5: Solve for x
   x = 12,398.78/100.05
6. Step 6: Final answer
   x = 123.93