Finding the Third Proportional to 521.91 and 812.72

Step by Step Solution

1. Step 1: Write the proportion equation
   521.91 : 812.72 = 812.72 : x
2. Step 2: Convert to fraction form
   521.91/812.72 = 812.72/x
3. Step 3: Cross multiply
   521.91x = 812.72 × 812.72
4. Step 4: Simplify right side
   521.91x = 660,511.77
5. Step 5: Solve for x
   x = 660,511.77/521.91
6. Step 6: Final answer
   x = 1,265.58