Finding the Fourth Proportional to 2,618.69, 3,928.74 and 887.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,618.69 : 3,928.74 = 887.31 : x
2. Step 2: Convert to fraction form
   2,618.69/3,928.74 = 887.31/x
3. Step 3: Cross multiply
   2,618.69x = 3,928.74 × 887.31
4. Step 4: Simplify right side
   2,618.69x = 3,486,010.29
5. Step 5: Solve for x
   x = 3,486,010.29/2,618.69
6. Step 6: Final answer
   x = 1,331.20