Finding the Fourth Proportional to 109.17, 149.94 and 90.71

Step by Step Solution

1. Step 1: Write the proportion equation
   109.17 : 149.94 = 90.71 : x
2. Step 2: Convert to fraction form
   109.17/149.94 = 90.71/x
3. Step 3: Cross multiply
   109.17x = 149.94 × 90.71
4. Step 4: Simplify right side
   109.17x = 13,601.06
5. Step 5: Solve for x
   x = 13,601.06/109.17
6. Step 6: Final answer
   x = 124.59