Finding the Fourth Proportional to 1,685.91, 2,525.18 and 1,390.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,685.91 : 2,525.18 = 1,390.09 : x
2. Step 2: Convert to fraction form
   1,685.91/2,525.18 = 1,390.09/x
3. Step 3: Cross multiply
   1,685.91x = 2,525.18 × 1,390.09
4. Step 4: Simplify right side
   1,685.91x = 3,510,224.63
5. Step 5: Solve for x
   x = 3,510,224.63/1,685.91
6. Step 6: Final answer
   x = 2,082.09