Finding the Third Proportional to 1,421.72 and 2,121.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,421.72 : 2,121.61 = 2,121.61 : x
2. Step 2: Convert to fraction form
   1,421.72/2,121.61 = 2,121.61/x
3. Step 3: Cross multiply
   1,421.72x = 2,121.61 × 2,121.61
4. Step 4: Simplify right side
   1,421.72x = 4,501,226.34
5. Step 5: Solve for x
   x = 4,501,226.34/1,421.72
6. Step 6: Final answer
   x = 3,166.05