Finding the Fourth Proportional to 2,381.55, 3,571.47 and 921.21

Step by Step Solution

1. Step 1: Write the proportion equation
   2,381.55 : 3,571.47 = 921.21 : x
2. Step 2: Convert to fraction form
   2,381.55/3,571.47 = 921.21/x
3. Step 3: Cross multiply
   2,381.55x = 3,571.47 × 921.21
4. Step 4: Simplify right side
   2,381.55x = 3,290,073.88
5. Step 5: Solve for x
   x = 3,290,073.88/2,381.55
6. Step 6: Final answer
   x = 1,381.48