Finding the Fourth Proportional to 1,389.57, 2,085.33 and 773.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.57 : 2,085.33 = 773.76 : x
2. Step 2: Convert to fraction form
   1,389.57/2,085.33 = 773.76/x
3. Step 3: Cross multiply
   1,389.57x = 2,085.33 × 773.76
4. Step 4: Simplify right side
   1,389.57x = 1,613,544.94
5. Step 5: Solve for x
   x = 1,613,544.94/1,389.57
6. Step 6: Final answer
   x = 1,161.18