Finding the Fourth Proportional to 1,111.17, 1,661.99 and 647.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.17 : 1,661.99 = 647.79 : x
2. Step 2: Convert to fraction form
   1,111.17/1,661.99 = 647.79/x
3. Step 3: Cross multiply
   1,111.17x = 1,661.99 × 647.79
4. Step 4: Simplify right side
   1,111.17x = 1,076,617.26
5. Step 5: Solve for x
   x = 1,076,617.26/1,111.17
6. Step 6: Final answer
   x = 968.90