Finding the Fourth Proportional to 2,478.80, 3,420.72 and 1,359.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,478.80 : 3,420.72 = 1,359.72 : x
2. Step 2: Convert to fraction form
   2,478.80/3,420.72 = 1,359.72/x
3. Step 3: Cross multiply
   2,478.80x = 3,420.72 × 1,359.72
4. Step 4: Simplify right side
   2,478.80x = 4,651,221.40
5. Step 5: Solve for x
   x = 4,651,221.40/2,478.80
6. Step 6: Final answer
   x = 1,876.40