Finding the Fourth Proportional to 3,715.98, 5,128.06 and 2,100.80

Step by Step Solution

1. Step 1: Write the proportion equation
   3,715.98 : 5,128.06 = 2,100.80 : x
2. Step 2: Convert to fraction form
   3,715.98/5,128.06 = 2,100.80/x
3. Step 3: Cross multiply
   3,715.98x = 5,128.06 × 2,100.80
4. Step 4: Simplify right side
   3,715.98x = 10,773,028.45
5. Step 5: Solve for x
   x = 10,773,028.45/3,715.98
6. Step 6: Final answer
   x = 2,899.11