Finding the Third Proportional to 1,390.69 and 2,165.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.69 : 2,165.81 = 2,165.81 : x
2. Step 2: Convert to fraction form
   1,390.69/2,165.81 = 2,165.81/x
3. Step 3: Cross multiply
   1,390.69x = 2,165.81 × 2,165.81
4. Step 4: Simplify right side
   1,390.69x = 4,690,743.79
5. Step 5: Solve for x
   x = 4,690,743.79/1,390.69
6. Step 6: Final answer
   x = 3,372.97