Finding the Fourth Proportional to 1,389.12, 1,917.21 and 799.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.12 : 1,917.21 = 799.53 : x
2. Step 2: Convert to fraction form
   1,389.12/1,917.21 = 799.53/x
3. Step 3: Cross multiply
   1,389.12x = 1,917.21 × 799.53
4. Step 4: Simplify right side
   1,389.12x = 1,532,866.91
5. Step 5: Solve for x
   x = 1,532,866.91/1,389.12
6. Step 6: Final answer
   x = 1,103.48