Finding the Fourth Proportional to 1,428.16, 1,970.17 and 1,008.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.16 : 1,970.17 = 1,008.58 : x
2. Step 2: Convert to fraction form
   1,428.16/1,970.17 = 1,008.58/x
3. Step 3: Cross multiply
   1,428.16x = 1,970.17 × 1,008.58
4. Step 4: Simplify right side
   1,428.16x = 1,987,074.06
5. Step 5: Solve for x
   x = 1,987,074.06/1,428.16
6. Step 6: Final answer
   x = 1,391.35