Finding the Fourth Proportional to 3,986.15, 5,978.34 and 1,520.10

Step by Step Solution

1. Step 1: Write the proportion equation
   3,986.15 : 5,978.34 = 1,520.10 : x
2. Step 2: Convert to fraction form
   3,986.15/5,978.34 = 1,520.10/x
3. Step 3: Cross multiply
   3,986.15x = 5,978.34 × 1,520.10
4. Step 4: Simplify right side
   3,986.15x = 9,087,674.63
5. Step 5: Solve for x
   x = 9,087,674.63/3,986.15
6. Step 6: Final answer
   x = 2,279.82