Finding the Third Proportional to 1,216.50 and 1,640.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.50 : 1,640.75 = 1,640.75 : x
2. Step 2: Convert to fraction form
   1,216.50/1,640.75 = 1,640.75/x
3. Step 3: Cross multiply
   1,216.50x = 1,640.75 × 1,640.75
4. Step 4: Simplify right side
   1,216.50x = 2,692,060.56
5. Step 5: Solve for x
   x = 2,692,060.56/1,216.50
6. Step 6: Final answer
   x = 2,212.96