Finding the Fourth Proportional to 1,389.86, 2,085.63 and 806.00

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.86 : 2,085.63 = 806.00 : x
2. Step 2: Convert to fraction form
   1,389.86/2,085.63 = 806.00/x
3. Step 3: Cross multiply
   1,389.86x = 2,085.63 × 806.00
4. Step 4: Simplify right side
   1,389.86x = 1,681,020.59
5. Step 5: Solve for x
   x = 1,681,020.59/1,389.86
6. Step 6: Final answer
   x = 1,209.49