Finding the Fourth Proportional to 2,991.78, 4,480.71 and 2,887.96

Step by Step Solution

1. Step 1: Write the proportion equation
   2,991.78 : 4,480.71 = 2,887.96 : x
2. Step 2: Convert to fraction form
   2,991.78/4,480.71 = 2,887.96/x
3. Step 3: Cross multiply
   2,991.78x = 4,480.71 × 2,887.96
4. Step 4: Simplify right side
   2,991.78x = 12,940,111.25
5. Step 5: Solve for x
   x = 12,940,111.25/2,991.78
6. Step 6: Final answer
   x = 4,325.22