Finding the Fourth Proportional to 2,615.87, 3,609.89 and 1,420.85

Step by Step Solution

1. Step 1: Write the proportion equation
   2,615.87 : 3,609.89 = 1,420.85 : x
2. Step 2: Convert to fraction form
   2,615.87/3,609.89 = 1,420.85/x
3. Step 3: Cross multiply
   2,615.87x = 3,609.89 × 1,420.85
4. Step 4: Simplify right side
   2,615.87x = 5,129,112.21
5. Step 5: Solve for x
   x = 5,129,112.21/2,615.87
6. Step 6: Final answer
   x = 1,960.77