Finding the Fourth Proportional to 1,886.40, 2,603.79 and 1,223.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,886.40 : 2,603.79 = 1,223.31 : x
2. Step 2: Convert to fraction form
   1,886.40/2,603.79 = 1,223.31/x
3. Step 3: Cross multiply
   1,886.40x = 2,603.79 × 1,223.31
4. Step 4: Simplify right side
   1,886.40x = 3,185,242.34
5. Step 5: Solve for x
   x = 3,185,242.34/1,886.40
6. Step 6: Final answer
   x = 1,688.53