Finding the Fourth Proportional to 2,720.79, 4,081.59 and 871.74

Step by Step Solution

1. Step 1: Write the proportion equation
   2,720.79 : 4,081.59 = 871.74 : x
2. Step 2: Convert to fraction form
   2,720.79/4,081.59 = 871.74/x
3. Step 3: Cross multiply
   2,720.79x = 4,081.59 × 871.74
4. Step 4: Simplify right side
   2,720.79x = 3,558,085.27
5. Step 5: Solve for x
   x = 3,558,085.27/2,720.79
6. Step 6: Final answer
   x = 1,307.74