Finding the Fourth Proportional to 1,053.02, 1,577.78 and 640.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,053.02 : 1,577.78 = 640.91 : x
2. Step 2: Convert to fraction form
   1,053.02/1,577.78 = 640.91/x
3. Step 3: Cross multiply
   1,053.02x = 1,577.78 × 640.91
4. Step 4: Simplify right side
   1,053.02x = 1,011,203.89
5. Step 5: Solve for x
   x = 1,011,203.89/1,053.02
6. Step 6: Final answer
   x = 960.29