Finding the Fourth Proportional to 1,422.50, 2,131.89 and 728.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,422.50 : 2,131.89 = 728.58 : x
2. Step 2: Convert to fraction form
   1,422.50/2,131.89 = 728.58/x
3. Step 3: Cross multiply
   1,422.50x = 2,131.89 × 728.58
4. Step 4: Simplify right side
   1,422.50x = 1,553,252.42
5. Step 5: Solve for x
   x = 1,553,252.42/1,422.50
6. Step 6: Final answer
   x = 1,091.92