Finding the Fourth Proportional to 99.38, 149.72 and 90.12

Step by Step Solution

1. Step 1: Write the proportion equation
   99.38 : 149.72 = 90.12 : x
2. Step 2: Convert to fraction form
   99.38/149.72 = 90.12/x
3. Step 3: Cross multiply
   99.38x = 149.72 × 90.12
4. Step 4: Simplify right side
   99.38x = 13,492.32
5. Step 5: Solve for x
   x = 13,492.32/99.38
6. Step 6: Final answer
   x = 135.77