Finding the Fourth Proportional to 1,288.23, 1,776.38 and 938.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.23 : 1,776.38 = 938.31 : x
2. Step 2: Convert to fraction form
   1,288.23/1,776.38 = 938.31/x
3. Step 3: Cross multiply
   1,288.23x = 1,776.38 × 938.31
4. Step 4: Simplify right side
   1,288.23x = 1,666,790.43
5. Step 5: Solve for x
   x = 1,666,790.43/1,288.23
6. Step 6: Final answer
   x = 1,293.86