Finding the Fourth Proportional to 1,490.72, 2,238.16 and 760.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,490.72 : 2,238.16 = 760.80 : x
2. Step 2: Convert to fraction form
   1,490.72/2,238.16 = 760.80/x
3. Step 3: Cross multiply
   1,490.72x = 2,238.16 × 760.80
4. Step 4: Simplify right side
   1,490.72x = 1,702,792.13
5. Step 5: Solve for x
   x = 1,702,792.13/1,490.72
6. Step 6: Final answer
   x = 1,142.26