Finding the Fourth Proportional to 1,386.63, 2,078.21 and 693.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.63 : 2,078.21 = 693.50 : x
2. Step 2: Convert to fraction form
   1,386.63/2,078.21 = 693.50/x
3. Step 3: Cross multiply
   1,386.63x = 2,078.21 × 693.50
4. Step 4: Simplify right side
   1,386.63x = 1,441,224.78
5. Step 5: Solve for x
   x = 1,441,224.78/1,386.63
6. Step 6: Final answer
   x = 1,039.37