Finding the Fourth Proportional to 2,861.06, 4,291.01 and 780.89

Step by Step Solution

1. Step 1: Write the proportion equation
   2,861.06 : 4,291.01 = 780.89 : x
2. Step 2: Convert to fraction form
   2,861.06/4,291.01 = 780.89/x
3. Step 3: Cross multiply
   2,861.06x = 4,291.01 × 780.89
4. Step 4: Simplify right side
   2,861.06x = 3,350,784.37
5. Step 5: Solve for x
   x = 3,350,784.37/2,861.06
6. Step 6: Final answer
   x = 1,171.17