Finding the Fourth Proportional to 99.98, 137.83 and 87.63

Step by Step Solution

1. Step 1: Write the proportion equation
   99.98 : 137.83 = 87.63 : x
2. Step 2: Convert to fraction form
   99.98/137.83 = 87.63/x
3. Step 3: Cross multiply
   99.98x = 137.83 × 87.63
4. Step 4: Simplify right side
   99.98x = 12,078.00
5. Step 5: Solve for x
   x = 12,078.00/99.98
6. Step 6: Final answer
   x = 120.80