Finding the Fourth Proportional to 1,008.47, 1,388.34 and 870.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,008.47 : 1,388.34 = 870.41 : x
2. Step 2: Convert to fraction form
   1,008.47/1,388.34 = 870.41/x
3. Step 3: Cross multiply
   1,008.47x = 1,388.34 × 870.41
4. Step 4: Simplify right side
   1,008.47x = 1,208,428.49
5. Step 5: Solve for x
   x = 1,208,428.49/1,008.47
6. Step 6: Final answer
   x = 1,198.28