Finding the Fourth Proportional to 3,870.16, 5,340.86 and 2,101.80

Step by Step Solution

1. Step 1: Write the proportion equation
   3,870.16 : 5,340.86 = 2,101.80 : x
2. Step 2: Convert to fraction form
   3,870.16/5,340.86 = 2,101.80/x
3. Step 3: Cross multiply
   3,870.16x = 5,340.86 × 2,101.80
4. Step 4: Simplify right side
   3,870.16x = 11,225,419.55
5. Step 5: Solve for x
   x = 11,225,419.55/3,870.16
6. Step 6: Final answer
   x = 2,900.51