Finding the Fourth Proportional to 1,392.82, 2,088.15 and 815.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,392.82 : 2,088.15 = 815.02 : x
2. Step 2: Convert to fraction form
   1,392.82/2,088.15 = 815.02/x
3. Step 3: Cross multiply
   1,392.82x = 2,088.15 × 815.02
4. Step 4: Simplify right side
   1,392.82x = 1,701,884.01
5. Step 5: Solve for x
   x = 1,701,884.01/1,392.82
6. Step 6: Final answer
   x = 1,221.90