Finding the Fourth Proportional to 1,369.89, 1,889.98 and 780.01

Step by Step Solution

1. Step 1: Write the proportion equation
   1,369.89 : 1,889.98 = 780.01 : x
2. Step 2: Convert to fraction form
   1,369.89/1,889.98 = 780.01/x
3. Step 3: Cross multiply
   1,369.89x = 1,889.98 × 780.01
4. Step 4: Simplify right side
   1,369.89x = 1,474,195.80
5. Step 5: Solve for x
   x = 1,474,195.80/1,369.89
6. Step 6: Final answer
   x = 1,076.14