Finding the Fourth Proportional to 2,221.50, 3,065.67 and 1,290

Step by Step Solution

1. Step 1: Write the proportion equation
   2,221.50 : 3,065.67 = 1,290 : x
2. Step 2: Convert to fraction form
   2,221.50/3,065.67 = 1,290/x
3. Step 3: Cross multiply
   2,221.50x = 3,065.67 × 1,290
4. Step 4: Simplify right side
   2,221.50x = 3,954,714.30
5. Step 5: Solve for x
   x = 3,954,714.30/2,221.50
6. Step 6: Final answer
   x = 1,780.20