Finding the Third Proportional to 811.82 and 1,290.58

Step by Step Solution

1. Step 1: Write the proportion equation
   811.82 : 1,290.58 = 1,290.58 : x
2. Step 2: Convert to fraction form
   811.82/1,290.58 = 1,290.58/x
3. Step 3: Cross multiply
   811.82x = 1,290.58 × 1,290.58
4. Step 4: Simplify right side
   811.82x = 1,665,600.72
5. Step 5: Solve for x
   x = 1,665,600.72/811.82
6. Step 6: Final answer
   x = 2,051.69