Finding the Fourth Proportional to 2,071.70, 3,105.15 and 838.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,071.70 : 3,105.15 = 838.30 : x
2. Step 2: Convert to fraction form
   2,071.70/3,105.15 = 838.30/x
3. Step 3: Cross multiply
   2,071.70x = 3,105.15 × 838.30
4. Step 4: Simplify right side
   2,071.70x = 2,603,047.25
5. Step 5: Solve for x
   x = 2,603,047.25/2,071.70
6. Step 6: Final answer
   x = 1,256.48