Finding the Fourth Proportional to 1,229.72, 1,841.69 and 643.32

Step by Step Solution

1. Step 1: Write the proportion equation
   1,229.72 : 1,841.69 = 643.32 : x
2. Step 2: Convert to fraction form
   1,229.72/1,841.69 = 643.32/x
3. Step 3: Cross multiply
   1,229.72x = 1,841.69 × 643.32
4. Step 4: Simplify right side
   1,229.72x = 1,184,792.79
5. Step 5: Solve for x
   x = 1,184,792.79/1,229.72
6. Step 6: Final answer
   x = 963.47