Finding the Fourth Proportional to 2,015.59, 2,780.12 and 1,642.57

Step by Step Solution

1. Step 1: Write the proportion equation
   2,015.59 : 2,780.12 = 1,642.57 : x
2. Step 2: Convert to fraction form
   2,015.59/2,780.12 = 1,642.57/x
3. Step 3: Cross multiply
   2,015.59x = 2,780.12 × 1,642.57
4. Step 4: Simplify right side
   2,015.59x = 4,566,533.50
5. Step 5: Solve for x
   x = 4,566,533.50/2,015.59
6. Step 6: Final answer
   x = 2,265.61