Finding the Third Proportional to 61,213.50 and 129,780

Step by Step Solution

1. Step 1: Write the proportion equation
   61,213.50 : 129,780 = 129,780 : x
2. Step 2: Convert to fraction form
   61,213.50/129,780 = 129,780/x
3. Step 3: Cross multiply
   61,213.50x = 129,780 × 129,780
4. Step 4: Simplify right side
   61,213.50x = 16,842,848,400
5. Step 5: Solve for x
   x = 16,842,848,400/61,213.50
6. Step 6: Final answer
   x = 275,149.25