Finding the Fourth Proportional to 3,699.81, 5,106.51 and 2,128.77

Step by Step Solution

1. Step 1: Write the proportion equation
   3,699.81 : 5,106.51 = 2,128.77 : x
2. Step 2: Convert to fraction form
   3,699.81/5,106.51 = 2,128.77/x
3. Step 3: Cross multiply
   3,699.81x = 5,106.51 × 2,128.77
4. Step 4: Simplify right side
   3,699.81x = 10,870,585.29
5. Step 5: Solve for x
   x = 10,870,585.29/3,699.81
6. Step 6: Final answer
   x = 2,938.15