Finding the Third Proportional to 31,620 and 69,139.50

Step by Step Solution

1. Step 1: Write the proportion equation
   31,620 : 69,139.50 = 69,139.50 : x
2. Step 2: Convert to fraction form
   31,620/69,139.50 = 69,139.50/x
3. Step 3: Cross multiply
   31,620x = 69,139.50 × 69,139.50
4. Step 4: Simplify right side
   31,620x = 4,780,270,460.25
5. Step 5: Solve for x
   x = 4,780,270,460.25/31,620
6. Step 6: Final answer
   x = 151,178.70