Finding the Fourth Proportional to 2,139.88, 3,210.30 and 679.08

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.88 : 3,210.30 = 679.08 : x
2. Step 2: Convert to fraction form
   2,139.88/3,210.30 = 679.08/x
3. Step 3: Cross multiply
   2,139.88x = 3,210.30 × 679.08
4. Step 4: Simplify right side
   2,139.88x = 2,180,050.52
5. Step 5: Solve for x
   x = 2,180,050.52/2,139.88
6. Step 6: Final answer
   x = 1,018.77