Finding the Fourth Proportional to 1,385.82, 1,912.28 and 826.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.82 : 1,912.28 = 826.31 : x
2. Step 2: Convert to fraction form
   1,385.82/1,912.28 = 826.31/x
3. Step 3: Cross multiply
   1,385.82x = 1,912.28 × 826.31
4. Step 4: Simplify right side
   1,385.82x = 1,580,136.09
5. Step 5: Solve for x
   x = 1,580,136.09/1,385.82
6. Step 6: Final answer
   x = 1,140.22