Finding the Fourth Proportional to 1,288.09, 1,934.72 and 769.11

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.09 : 1,934.72 = 769.11 : x
2. Step 2: Convert to fraction form
   1,288.09/1,934.72 = 769.11/x
3. Step 3: Cross multiply
   1,288.09x = 1,934.72 × 769.11
4. Step 4: Simplify right side
   1,288.09x = 1,488,012.50
5. Step 5: Solve for x
   x = 1,488,012.50/1,288.09
6. Step 6: Final answer
   x = 1,155.21