Finding the Fourth Proportional to 1,389.37, 1,916.66 and 917.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.37 : 1,916.66 = 917.45 : x
2. Step 2: Convert to fraction form
   1,389.37/1,916.66 = 917.45/x
3. Step 3: Cross multiply
   1,389.37x = 1,916.66 × 917.45
4. Step 4: Simplify right side
   1,389.37x = 1,758,439.72
5. Step 5: Solve for x
   x = 1,758,439.72/1,389.37
6. Step 6: Final answer
   x = 1,265.64