Finding the Fourth Proportional to 1,638.72, 2,261.74 and 940.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,638.72 : 2,261.74 = 940.09 : x
2. Step 2: Convert to fraction form
   1,638.72/2,261.74 = 940.09/x
3. Step 3: Cross multiply
   1,638.72x = 2,261.74 × 940.09
4. Step 4: Simplify right side
   1,638.72x = 2,126,239.16
5. Step 5: Solve for x
   x = 2,126,239.16/1,638.72
6. Step 6: Final answer
   x = 1,297.50