Finding the Fourth Proportional to 7,022.40, 9,690.72 and 3,878.40

Step by Step Solution

1. Step 1: Write the proportion equation
   7,022.40 : 9,690.72 = 3,878.40 : x
2. Step 2: Convert to fraction form
   7,022.40/9,690.72 = 3,878.40/x
3. Step 3: Cross multiply
   7,022.40x = 9,690.72 × 3,878.40
4. Step 4: Simplify right side
   7,022.40x = 37,584,488.45
5. Step 5: Solve for x
   x = 37,584,488.45/7,022.40
6. Step 6: Final answer
   x = 5,352.09