Finding the Fourth Proportional to 1,091.91, 1,506.71 and 619.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,091.91 : 1,506.71 = 619.86 : x
2. Step 2: Convert to fraction form
   1,091.91/1,506.71 = 619.86/x
3. Step 3: Cross multiply
   1,091.91x = 1,506.71 × 619.86
4. Step 4: Simplify right side
   1,091.91x = 933,946.16
5. Step 5: Solve for x
   x = 933,946.16/1,091.91
6. Step 6: Final answer
   x = 855.33