Finding the Third Proportional to 521.06 and 810.56

Step by Step Solution

1. Step 1: Write the proportion equation
   521.06 : 810.56 = 810.56 : x
2. Step 2: Convert to fraction form
   521.06/810.56 = 810.56/x
3. Step 3: Cross multiply
   521.06x = 810.56 × 810.56
4. Step 4: Simplify right side
   521.06x = 657,011.57
5. Step 5: Solve for x
   x = 657,011.57/521.06
6. Step 6: Final answer
   x = 1,260.91