Finding the Fourth Proportional to 2,861.70, 4,290.72 and 1,217.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,861.70 : 4,290.72 = 1,217.40 : x
2. Step 2: Convert to fraction form
   2,861.70/4,290.72 = 1,217.40/x
3. Step 3: Cross multiply
   2,861.70x = 4,290.72 × 1,217.40
4. Step 4: Simplify right side
   2,861.70x = 5,223,522.53
5. Step 5: Solve for x
   x = 5,223,522.53/2,861.70
6. Step 6: Final answer
   x = 1,825.32