Finding the Fourth Proportional to 1,405.67, 1,939.82 and 808.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.67 : 1,939.82 = 808.21 : x
2. Step 2: Convert to fraction form
   1,405.67/1,939.82 = 808.21/x
3. Step 3: Cross multiply
   1,405.67x = 1,939.82 × 808.21
4. Step 4: Simplify right side
   1,405.67x = 1,567,772.22
5. Step 5: Solve for x
   x = 1,567,772.22/1,405.67
6. Step 6: Final answer
   x = 1,115.32