Finding the Fourth Proportional to 1,199.89, 1,799.89 and 419.97

Step by Step Solution

1. Step 1: Write the proportion equation
   1,199.89 : 1,799.89 = 419.97 : x
2. Step 2: Convert to fraction form
   1,199.89/1,799.89 = 419.97/x
3. Step 3: Cross multiply
   1,199.89x = 1,799.89 × 419.97
4. Step 4: Simplify right side
   1,199.89x = 755,899.80
5. Step 5: Solve for x
   x = 755,899.80/1,199.89
6. Step 6: Final answer
   x = 629.97