Finding the Fourth Proportional to 2,261.91, 3,392.04 and 780.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,261.91 : 3,392.04 = 780.72 : x
2. Step 2: Convert to fraction form
   2,261.91/3,392.04 = 780.72/x
3. Step 3: Cross multiply
   2,261.91x = 3,392.04 × 780.72
4. Step 4: Simplify right side
   2,261.91x = 2,648,233.47
5. Step 5: Solve for x
   x = 2,648,233.47/2,261.91
6. Step 6: Final answer
   x = 1,170.80