Finding the Fourth Proportional to 810.72, 1,224.48 and 810.72

Step by Step Solution

1. Step 1: Write the proportion equation
   810.72 : 1,224.48 = 810.72 : x
2. Step 2: Convert to fraction form
   810.72/1,224.48 = 810.72/x
3. Step 3: Cross multiply
   810.72x = 1,224.48 × 810.72
4. Step 4: Simplify right side
   810.72x = 992,710.43
5. Step 5: Solve for x
   x = 992,710.43/810.72
6. Step 6: Final answer
   x = 1,224.48