Finding the Third Proportional to 78,778.50 and 103,405.50

Step by Step Solution

1. Step 1: Write the proportion equation
   78,778.50 : 103,405.50 = 103,405.50 : x
2. Step 2: Convert to fraction form
   78,778.50/103,405.50 = 103,405.50/x
3. Step 3: Cross multiply
   78,778.50x = 103,405.50 × 103,405.50
4. Step 4: Simplify right side
   78,778.50x = 10,692,697,430.25
5. Step 5: Solve for x
   x = 10,692,697,430.25/78,778.50
6. Step 6: Final answer
   x = 135,731.16