Finding the Third Proportional to 7,978.50 and 18,438.75

Step by Step Solution

1. Step 1: Write the proportion equation
   7,978.50 : 18,438.75 = 18,438.75 : x
2. Step 2: Convert to fraction form
   7,978.50/18,438.75 = 18,438.75/x
3. Step 3: Cross multiply
   7,978.50x = 18,438.75 × 18,438.75
4. Step 4: Simplify right side
   7,978.50x = 339,987,501.56
5. Step 5: Solve for x
   x = 339,987,501.56/7,978.50
6. Step 6: Final answer
   x = 42,612.96