Finding the Fourth Proportional to 1,288.53, 1,931.67 and 558

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.53 : 1,931.67 = 558 : x
2. Step 2: Convert to fraction form
   1,288.53/1,931.67 = 558/x
3. Step 3: Cross multiply
   1,288.53x = 1,931.67 × 558
4. Step 4: Simplify right side
   1,288.53x = 1,077,871.86
5. Step 5: Solve for x
   x = 1,077,871.86/1,288.53
6. Step 6: Final answer
   x = 836.51