Finding the Fourth Proportional to 1,561.72, 2,339.80 and 1,392.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.72 : 2,339.80 = 1,392.20 : x
2. Step 2: Convert to fraction form
   1,561.72/2,339.80 = 1,392.20/x
3. Step 3: Cross multiply
   1,561.72x = 2,339.80 × 1,392.20
4. Step 4: Simplify right side
   1,561.72x = 3,257,469.56
5. Step 5: Solve for x
   x = 3,257,469.56/1,561.72
6. Step 6: Final answer
   x = 2,085.82