Finding the Third Proportional to 31,218.50 and 67,980.50

Step by Step Solution

1. Step 1: Write the proportion equation
   31,218.50 : 67,980.50 = 67,980.50 : x
2. Step 2: Convert to fraction form
   31,218.50/67,980.50 = 67,980.50/x
3. Step 3: Cross multiply
   31,218.50x = 67,980.50 × 67,980.50
4. Step 4: Simplify right side
   31,218.50x = 4,621,348,380.25
5. Step 5: Solve for x
   x = 4,621,348,380.25/31,218.50
6. Step 6: Final answer
   x = 148,032.36