Finding the Fourth Proportional to 2,220, 3,063.72 and 1,288.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,220 : 3,063.72 = 1,288.80 : x
2. Step 2: Convert to fraction form
   2,220/3,063.72 = 1,288.80/x
3. Step 3: Cross multiply
   2,220x = 3,063.72 × 1,288.80
4. Step 4: Simplify right side
   2,220x = 3,948,522.34
5. Step 5: Solve for x
   x = 3,948,522.34/2,220
6. Step 6: Final answer
   x = 1,778.61