Finding the Fourth Proportional to 3,870.78, 5,340.78 and 2,191.81

Step by Step Solution

1. Step 1: Write the proportion equation
   3,870.78 : 5,340.78 = 2,191.81 : x
2. Step 2: Convert to fraction form
   3,870.78/5,340.78 = 2,191.81/x
3. Step 3: Cross multiply
   3,870.78x = 5,340.78 × 2,191.81
4. Step 4: Simplify right side
   3,870.78x = 11,705,975.01
5. Step 5: Solve for x
   x = 11,705,975.01/3,870.78
6. Step 6: Final answer
   x = 3,024.19