Finding the Fourth Proportional to 2,591.72, 3,886.37 and 836.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,591.72 : 3,886.37 = 836.40 : x
2. Step 2: Convert to fraction form
   2,591.72/3,886.37 = 836.40/x
3. Step 3: Cross multiply
   2,591.72x = 3,886.37 × 836.40
4. Step 4: Simplify right side
   2,591.72x = 3,250,559.87
5. Step 5: Solve for x
   x = 3,250,559.87/2,591.72
6. Step 6: Final answer
   x = 1,254.21