Finding the Fourth Proportional to 1,521.72, 2,100.20 and 858.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,521.72 : 2,100.20 = 858.74 : x
2. Step 2: Convert to fraction form
   1,521.72/2,100.20 = 858.74/x
3. Step 3: Cross multiply
   1,521.72x = 2,100.20 × 858.74
4. Step 4: Simplify right side
   1,521.72x = 1,803,510.95
5. Step 5: Solve for x
   x = 1,803,510.95/1,521.72
6. Step 6: Final answer
   x = 1,185.18