Finding the Fourth Proportional to 1,288.18, 1,931.72 and 557.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.18 : 1,931.72 = 557.22 : x
2. Step 2: Convert to fraction form
   1,288.18/1,931.72 = 557.22/x
3. Step 3: Cross multiply
   1,288.18x = 1,931.72 × 557.22
4. Step 4: Simplify right side
   1,288.18x = 1,076,397.48
5. Step 5: Solve for x
   x = 1,076,397.48/1,288.18
6. Step 6: Final answer
   x = 835.59