Finding the Third Proportional to 51,291 and 78,790.50

Step by Step Solution

1. Step 1: Write the proportion equation
   51,291 : 78,790.50 = 78,790.50 : x
2. Step 2: Convert to fraction form
   51,291/78,790.50 = 78,790.50/x
3. Step 3: Cross multiply
   51,291x = 78,790.50 × 78,790.50
4. Step 4: Simplify right side
   51,291x = 6,207,942,890.25
5. Step 5: Solve for x
   x = 6,207,942,890.25/51,291
6. Step 6: Final answer
   x = 121,033.77