Finding the Third Proportional to 2,128.80 and 2,931.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.80 : 2,931.31 = 2,931.31 : x
2. Step 2: Convert to fraction form
   2,128.80/2,931.31 = 2,931.31/x
3. Step 3: Cross multiply
   2,128.80x = 2,931.31 × 2,931.31
4. Step 4: Simplify right side
   2,128.80x = 8,592,555.76
5. Step 5: Solve for x
   x = 8,592,555.76/2,128.80
6. Step 6: Final answer
   x = 4,036.34