Finding the Fourth Proportional to 1,288.72, 1,934.34 and 918.93

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.72 : 1,934.34 = 918.93 : x
2. Step 2: Convert to fraction form
   1,288.72/1,934.34 = 918.93/x
3. Step 3: Cross multiply
   1,288.72x = 1,934.34 × 918.93
4. Step 4: Simplify right side
   1,288.72x = 1,777,523.06
5. Step 5: Solve for x
   x = 1,777,523.06/1,288.72
6. Step 6: Final answer
   x = 1,379.29