Finding the Third Proportional to 1,423.20 and 2,138.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,423.20 : 2,138.59 = 2,138.59 : x
2. Step 2: Convert to fraction form
   1,423.20/2,138.59 = 2,138.59/x
3. Step 3: Cross multiply
   1,423.20x = 2,138.59 × 2,138.59
4. Step 4: Simplify right side
   1,423.20x = 4,573,566.52
5. Step 5: Solve for x
   x = 4,573,566.52/1,423.20
6. Step 6: Final answer
   x = 3,213.59