Finding the Fourth Proportional to 1,380.51, 2,072.59 and 1,265.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.51 : 2,072.59 = 1,265.90 : x
2. Step 2: Convert to fraction form
   1,380.51/2,072.59 = 1,265.90/x
3. Step 3: Cross multiply
   1,380.51x = 2,072.59 × 1,265.90
4. Step 4: Simplify right side
   1,380.51x = 2,623,678.15
5. Step 5: Solve for x
   x = 2,623,678.15/1,380.51
6. Step 6: Final answer
   x = 1,900.51