Finding the Fourth Proportional to 2,547.89, 3,515.88 and 1,428.57

Step by Step Solution

1. Step 1: Write the proportion equation
   2,547.89 : 3,515.88 = 1,428.57 : x
2. Step 2: Convert to fraction form
   2,547.89/3,515.88 = 1,428.57/x
3. Step 3: Cross multiply
   2,547.89x = 3,515.88 × 1,428.57
4. Step 4: Simplify right side
   2,547.89x = 5,022,680.69
5. Step 5: Solve for x
   x = 5,022,680.69/2,547.89
6. Step 6: Final answer
   x = 1,971.31