Finding the Fourth Proportional to 1,911.71, 2,639.72 and 1,557.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,911.71 : 2,639.72 = 1,557.69 : x
2. Step 2: Convert to fraction form
   1,911.71/2,639.72 = 1,557.69/x
3. Step 3: Cross multiply
   1,911.71x = 2,639.72 × 1,557.69
4. Step 4: Simplify right side
   1,911.71x = 4,111,865.45
5. Step 5: Solve for x
   x = 4,111,865.45/1,911.71
6. Step 6: Final answer
   x = 2,150.88