Finding the Fourth Proportional to 93.15, 139.41 and 90.72

Step by Step Solution

1. Step 1: Write the proportion equation
   93.15 : 139.41 = 90.72 : x
2. Step 2: Convert to fraction form
   93.15/139.41 = 90.72/x
3. Step 3: Cross multiply
   93.15x = 139.41 × 90.72
4. Step 4: Simplify right side
   93.15x = 12,647.28
5. Step 5: Solve for x
   x = 12,647.28/93.15
6. Step 6: Final answer
   x = 135.77