Finding the Fourth Proportional to 1,420.27, 1,959.93 and 790.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,420.27 : 1,959.93 = 790.80 : x
2. Step 2: Convert to fraction form
   1,420.27/1,959.93 = 790.80/x
3. Step 3: Cross multiply
   1,420.27x = 1,959.93 × 790.80
4. Step 4: Simplify right side
   1,420.27x = 1,549,909.72
5. Step 5: Solve for x
   x = 1,549,909.72/1,420.27
6. Step 6: Final answer
   x = 1,091.28