Finding the Fourth Proportional to 3,111.91, 4,668.77 and 920.69

Step by Step Solution

1. Step 1: Write the proportion equation
   3,111.91 : 4,668.77 = 920.69 : x
2. Step 2: Convert to fraction form
   3,111.91/4,668.77 = 920.69/x
3. Step 3: Cross multiply
   3,111.91x = 4,668.77 × 920.69
4. Step 4: Simplify right side
   3,111.91x = 4,298,499.45
5. Step 5: Solve for x
   x = 4,298,499.45/3,111.91
6. Step 6: Final answer
   x = 1,381.31