Finding the Fourth Proportional to 2,620.53, 3,928.37 and 1,386.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,620.53 : 3,928.37 = 1,386.90 : x
2. Step 2: Convert to fraction form
   2,620.53/3,928.37 = 1,386.90/x
3. Step 3: Cross multiply
   2,620.53x = 3,928.37 × 1,386.90
4. Step 4: Simplify right side
   2,620.53x = 5,448,262.71
5. Step 5: Solve for x
   x = 5,448,262.71/2,620.53
6. Step 6: Final answer
   x = 2,079.07