Finding the Third Proportional to 2,178 and 5,431.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,178 : 5,431.50 = 5,431.50 : x
2. Step 2: Convert to fraction form
   2,178/5,431.50 = 5,431.50/x
3. Step 3: Cross multiply
   2,178x = 5,431.50 × 5,431.50
4. Step 4: Simplify right side
   2,178x = 29,501,192.25
5. Step 5: Solve for x
   x = 29,501,192.25/2,178
6. Step 6: Final answer
   x = 13,545.08