Finding the Fourth Proportional to 1,386.21, 1,912.49 and 826.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.21 : 1,912.49 = 826.30 : x
2. Step 2: Convert to fraction form
   1,386.21/1,912.49 = 826.30/x
3. Step 3: Cross multiply
   1,386.21x = 1,912.49 × 826.30
4. Step 4: Simplify right side
   1,386.21x = 1,580,280.92
5. Step 5: Solve for x
   x = 1,580,280.92/1,386.21
6. Step 6: Final answer
   x = 1,140.00