Finding the Fourth Proportional to 1,219.72, 1,830.12 and 570.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,219.72 : 1,830.12 = 570.40 : x
2. Step 2: Convert to fraction form
   1,219.72/1,830.12 = 570.40/x
3. Step 3: Cross multiply
   1,219.72x = 1,830.12 × 570.40
4. Step 4: Simplify right side
   1,219.72x = 1,043,900.45
5. Step 5: Solve for x
   x = 1,043,900.45/1,219.72
6. Step 6: Final answer
   x = 855.85