Finding the Fourth Proportional to 2,123.85, 3,186.15 and 807.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,123.85 : 3,186.15 = 807.72 : x
2. Step 2: Convert to fraction form
   2,123.85/3,186.15 = 807.72/x
3. Step 3: Cross multiply
   2,123.85x = 3,186.15 × 807.72
4. Step 4: Simplify right side
   2,123.85x = 2,573,503.62
5. Step 5: Solve for x
   x = 2,573,503.62/2,123.85
6. Step 6: Final answer
   x = 1,211.72