Finding the Fourth Proportional to 2,139.81, 3,210.78 and 1,202.17

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.81 : 3,210.78 = 1,202.17 : x
2. Step 2: Convert to fraction form
   2,139.81/3,210.78 = 1,202.17/x
3. Step 3: Cross multiply
   2,139.81x = 3,210.78 × 1,202.17
4. Step 4: Simplify right side
   2,139.81x = 3,859,903.39
5. Step 5: Solve for x
   x = 3,859,903.39/2,139.81
6. Step 6: Final answer
   x = 1,803.85