Finding the Fourth Proportional to 100.37, 149.91 and 90.72

Step by Step Solution

1. Step 1: Write the proportion equation
   100.37 : 149.91 = 90.72 : x
2. Step 2: Convert to fraction form
   100.37/149.91 = 90.72/x
3. Step 3: Cross multiply
   100.37x = 149.91 × 90.72
4. Step 4: Simplify right side
   100.37x = 13,599.84
5. Step 5: Solve for x
   x = 13,599.84/100.37
6. Step 6: Final answer
   x = 135.50