Finding the Fourth Proportional to 1,105.45, 1,657.64 and 643.37

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.45 : 1,657.64 = 643.37 : x
2. Step 2: Convert to fraction form
   1,105.45/1,657.64 = 643.37/x
3. Step 3: Cross multiply
   1,105.45x = 1,657.64 × 643.37
4. Step 4: Simplify right side
   1,105.45x = 1,066,469.17
5. Step 5: Solve for x
   x = 1,066,469.17/1,105.45
6. Step 6: Final answer
   x = 964.74