Finding the Fourth Proportional to 1,986.10, 2,786.30 and 1,986.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,986.10 : 2,786.30 = 1,986.10 : x
2. Step 2: Convert to fraction form
   1,986.10/2,786.30 = 1,986.10/x
3. Step 3: Cross multiply
   1,986.10x = 2,786.30 × 1,986.10
4. Step 4: Simplify right side
   1,986.10x = 5,533,870.43
5. Step 5: Solve for x
   x = 5,533,870.43/1,986.10
6. Step 6: Final answer
   x = 2,786.30