Finding the Fourth Proportional to 1,399.17, 2,084.40 and 1,335.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.17 : 2,084.40 = 1,335.99 : x
2. Step 2: Convert to fraction form
   1,399.17/2,084.40 = 1,335.99/x
3. Step 3: Cross multiply
   1,399.17x = 2,084.40 × 1,335.99
4. Step 4: Simplify right side
   1,399.17x = 2,784,737.56
5. Step 5: Solve for x
   x = 2,784,737.56/1,399.17
6. Step 6: Final answer
   x = 1,990.28