Finding the Fourth Proportional to 3,991.32, 5,513.40 and 3,618.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,991.32 : 5,513.40 = 3,618.72 : x
2. Step 2: Convert to fraction form
   3,991.32/5,513.40 = 3,618.72/x
3. Step 3: Cross multiply
   3,991.32x = 5,513.40 × 3,618.72
4. Step 4: Simplify right side
   3,991.32x = 19,951,450.85
5. Step 5: Solve for x
   x = 19,951,450.85/3,991.32
6. Step 6: Final answer
   x = 4,998.71