Finding the Fourth Proportional to 1,369.52, 1,889.72 and 780.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,369.52 : 1,889.72 = 780.02 : x
2. Step 2: Convert to fraction form
   1,369.52/1,889.72 = 780.02/x
3. Step 3: Cross multiply
   1,369.52x = 1,889.72 × 780.02
4. Step 4: Simplify right side
   1,369.52x = 1,474,019.39
5. Step 5: Solve for x
   x = 1,474,019.39/1,369.52
6. Step 6: Final answer
   x = 1,076.30