Finding the Fourth Proportional to 1,224.54, 1,689.72 and 720.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,224.54 : 1,689.72 = 720.30 : x
2. Step 2: Convert to fraction form
   1,224.54/1,689.72 = 720.30/x
3. Step 3: Cross multiply
   1,224.54x = 1,689.72 × 720.30
4. Step 4: Simplify right side
   1,224.54x = 1,217,105.32
5. Step 5: Solve for x
   x = 1,217,105.32/1,224.54
6. Step 6: Final answer
   x = 993.93