Finding the Fourth Proportional to 2,111.80, 3,162.30 and 1,679.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,111.80 : 3,162.30 = 1,679.80 : x
2. Step 2: Convert to fraction form
   2,111.80/3,162.30 = 1,679.80/x
3. Step 3: Cross multiply
   2,111.80x = 3,162.30 × 1,679.80
4. Step 4: Simplify right side
   2,111.80x = 5,312,031.54
5. Step 5: Solve for x
   x = 5,312,031.54/2,111.80
6. Step 6: Final answer
   x = 2,515.40