Finding the Fourth Proportional to 1,212.71, 1,673.69 and 715.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,212.71 : 1,673.69 = 715.28 : x
2. Step 2: Convert to fraction form
   1,212.71/1,673.69 = 715.28/x
3. Step 3: Cross multiply
   1,212.71x = 1,673.69 × 715.28
4. Step 4: Simplify right side
   1,212.71x = 1,197,145.04
5. Step 5: Solve for x
   x = 1,197,145.04/1,212.71
6. Step 6: Final answer
   x = 987.17