Finding the Fourth Proportional to 2,072.83, 3,109.37 and 840.21

Step by Step Solution

1. Step 1: Write the proportion equation
   2,072.83 : 3,109.37 = 840.21 : x
2. Step 2: Convert to fraction form
   2,072.83/3,109.37 = 840.21/x
3. Step 3: Cross multiply
   2,072.83x = 3,109.37 × 840.21
4. Step 4: Simplify right side
   2,072.83x = 2,612,523.77
5. Step 5: Solve for x
   x = 2,612,523.77/2,072.83
6. Step 6: Final answer
   x = 1,260.37