Finding the Fourth Proportional to 1,105.65, 1,657.91 and 643.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.65 : 1,657.91 = 643.52 : x
2. Step 2: Convert to fraction form
   1,105.65/1,657.91 = 643.52/x
3. Step 3: Cross multiply
   1,105.65x = 1,657.91 × 643.52
4. Step 4: Simplify right side
   1,105.65x = 1,066,904.00
5. Step 5: Solve for x
   x = 1,066,904.00/1,105.65
6. Step 6: Final answer
   x = 964.96