Finding the Fourth Proportional to 2,071.72, 3,108.66 and 840.04

Step by Step Solution

1. Step 1: Write the proportion equation
   2,071.72 : 3,108.66 = 840.04 : x
2. Step 2: Convert to fraction form
   2,071.72/3,108.66 = 840.04/x
3. Step 3: Cross multiply
   2,071.72x = 3,108.66 × 840.04
4. Step 4: Simplify right side
   2,071.72x = 2,611,398.75
5. Step 5: Solve for x
   x = 2,611,398.75/2,071.72
6. Step 6: Final answer
   x = 1,260.50