Finding the Fourth Proportional to 2,715.10, 4,071.42 and 865.86

Step by Step Solution

1. Step 1: Write the proportion equation
   2,715.10 : 4,071.42 = 865.86 : x
2. Step 2: Convert to fraction form
   2,715.10/4,071.42 = 865.86/x
3. Step 3: Cross multiply
   2,715.10x = 4,071.42 × 865.86
4. Step 4: Simplify right side
   2,715.10x = 3,525,279.72
5. Step 5: Solve for x
   x = 3,525,279.72/2,715.10
6. Step 6: Final answer
   x = 1,298.40