Finding the Fourth Proportional to 1,209.42, 1,811.59 and 722.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,209.42 : 1,811.59 = 722.21 : x
2. Step 2: Convert to fraction form
   1,209.42/1,811.59 = 722.21/x
3. Step 3: Cross multiply
   1,209.42x = 1,811.59 × 722.21
4. Step 4: Simplify right side
   1,209.42x = 1,308,348.41
5. Step 5: Solve for x
   x = 1,308,348.41/1,209.42
6. Step 6: Final answer
   x = 1,081.80