Finding the Fourth Proportional to 99.89, 137.87 and 91.69

Step by Step Solution

1. Step 1: Write the proportion equation
   99.89 : 137.87 = 91.69 : x
2. Step 2: Convert to fraction form
   99.89/137.87 = 91.69/x
3. Step 3: Cross multiply
   99.89x = 137.87 × 91.69
4. Step 4: Simplify right side
   99.89x = 12,641.30
5. Step 5: Solve for x
   x = 12,641.30/99.89
6. Step 6: Final answer
   x = 126.55