Finding the Fourth Proportional to 1,868.82, 2,578.64 and 1,311

Step by Step Solution

1. Step 1: Write the proportion equation
   1,868.82 : 2,578.64 = 1,311 : x
2. Step 2: Convert to fraction form
   1,868.82/2,578.64 = 1,311/x
3. Step 3: Cross multiply
   1,868.82x = 2,578.64 × 1,311
4. Step 4: Simplify right side
   1,868.82x = 3,380,597.04
5. Step 5: Solve for x
   x = 3,380,597.04/1,868.82
6. Step 6: Final answer
   x = 1,808.95