Finding the Fourth Proportional to 1,642.21, 2,264.73 and 1,223.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,642.21 : 2,264.73 = 1,223.59 : x
2. Step 2: Convert to fraction form
   1,642.21/2,264.73 = 1,223.59/x
3. Step 3: Cross multiply
   1,642.21x = 2,264.73 × 1,223.59
4. Step 4: Simplify right side
   1,642.21x = 2,771,100.98
5. Step 5: Solve for x
   x = 2,771,100.98/1,642.21
6. Step 6: Final answer
   x = 1,687.42