Finding the Third Proportional to 1,216.50 and 1,398.75

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.50 : 1,398.75 = 1,398.75 : x
2. Step 2: Convert to fraction form
   1,216.50/1,398.75 = 1,398.75/x
3. Step 3: Cross multiply
   1,216.50x = 1,398.75 × 1,398.75
4. Step 4: Simplify right side
   1,216.50x = 1,956,501.56
5. Step 5: Solve for x
   x = 1,956,501.56/1,216.50
6. Step 6: Final answer
   x = 1,608.30