Finding the Fourth Proportional to 2,215.12, 3,320.20 and 898.57

Step by Step Solution

1. Step 1: Write the proportion equation
   2,215.12 : 3,320.20 = 898.57 : x
2. Step 2: Convert to fraction form
   2,215.12/3,320.20 = 898.57/x
3. Step 3: Cross multiply
   2,215.12x = 3,320.20 × 898.57
4. Step 4: Simplify right side
   2,215.12x = 2,983,411.02
5. Step 5: Solve for x
   x = 2,983,411.02/2,215.12
6. Step 6: Final answer
   x = 1,346.84