Finding the Fourth Proportional to 2,547.60, 3,515.86 and 1,428.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,547.60 : 3,515.86 = 1,428.50 : x
2. Step 2: Convert to fraction form
   2,547.60/3,515.86 = 1,428.50/x
3. Step 3: Cross multiply
   2,547.60x = 3,515.86 × 1,428.50
4. Step 4: Simplify right side
   2,547.60x = 5,022,406.01
5. Step 5: Solve for x
   x = 5,022,406.01/2,547.60
6. Step 6: Final answer
   x = 1,971.43