Finding the Third Proportional to 1,221.33 and 2,157.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,221.33 : 2,157.89 = 2,157.89 : x
2. Step 2: Convert to fraction form
   1,221.33/2,157.89 = 2,157.89/x
3. Step 3: Cross multiply
   1,221.33x = 2,157.89 × 2,157.89
4. Step 4: Simplify right side
   1,221.33x = 4,656,491.95
5. Step 5: Solve for x
   x = 4,656,491.95/1,221.33
6. Step 6: Final answer
   x = 3,812.65