Finding the Fourth Proportional to 12,490.72, 18,721.44 and 5,090.56

Step by Step Solution

1. Step 1: Write the proportion equation
   12,490.72 : 18,721.44 = 5,090.56 : x
2. Step 2: Convert to fraction form
   12,490.72/18,721.44 = 5,090.56/x
3. Step 3: Cross multiply
   12,490.72x = 18,721.44 × 5,090.56
4. Step 4: Simplify right side
   12,490.72x = 95,302,613.61
5. Step 5: Solve for x
   x = 95,302,613.61/12,490.72
6. Step 6: Final answer
   x = 7,629.87