Finding the Fourth Proportional to 1,405.88, 1,939.56 and 816.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,405.88 : 1,939.56 = 816.20 : x
2. Step 2: Convert to fraction form
   1,405.88/1,939.56 = 816.20/x
3. Step 3: Cross multiply
   1,405.88x = 1,939.56 × 816.20
4. Step 4: Simplify right side
   1,405.88x = 1,583,068.87
5. Step 5: Solve for x
   x = 1,583,068.87/1,405.88
6. Step 6: Final answer
   x = 1,126.03