Finding the Fourth Proportional to 1,639.61, 2,264.50 and 1,271.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,639.61 : 2,264.50 = 1,271.05 : x
2. Step 2: Convert to fraction form
   1,639.61/2,264.50 = 1,271.05/x
3. Step 3: Cross multiply
   1,639.61x = 2,264.50 × 1,271.05
4. Step 4: Simplify right side
   1,639.61x = 2,878,283.89
5. Step 5: Solve for x
   x = 2,878,283.89/1,639.61
6. Step 6: Final answer
   x = 1,755.47