Finding the Third Proportional to 2,145 and 5,218.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,145 : 5,218.50 = 5,218.50 : x
2. Step 2: Convert to fraction form
   2,145/5,218.50 = 5,218.50/x
3. Step 3: Cross multiply
   2,145x = 5,218.50 × 5,218.50
4. Step 4: Simplify right side
   2,145x = 27,232,742.25
5. Step 5: Solve for x
   x = 27,232,742.25/2,145
6. Step 6: Final answer
   x = 12,695.92