Finding the Fourth Proportional to 1,722.40, 2,580.55 and 1,665.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,722.40 : 2,580.55 = 1,665.30 : x
2. Step 2: Convert to fraction form
   1,722.40/2,580.55 = 1,665.30/x
3. Step 3: Cross multiply
   1,722.40x = 2,580.55 × 1,665.30
4. Step 4: Simplify right side
   1,722.40x = 4,297,389.92
5. Step 5: Solve for x
   x = 4,297,389.92/1,722.40
6. Step 6: Final answer
   x = 2,495.00