Finding the Fourth Proportional to 1,681.23, 2,518.61 and 816.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,681.23 : 2,518.61 = 816.15 : x
2. Step 2: Convert to fraction form
   1,681.23/2,518.61 = 816.15/x
3. Step 3: Cross multiply
   1,681.23x = 2,518.61 × 816.15
4. Step 4: Simplify right side
   1,681.23x = 2,055,559.47
5. Step 5: Solve for x
   x = 2,055,559.47/1,681.23
6. Step 6: Final answer
   x = 1,222.65