Finding the Third Proportional to 391,275 and 621,931.50

Step by Step Solution

1. Step 1: Write the proportion equation
   391,275 : 621,931.50 = 621,931.50 : x
2. Step 2: Convert to fraction form
   391,275/621,931.50 = 621,931.50/x
3. Step 3: Cross multiply
   391,275x = 621,931.50 × 621,931.50
4. Step 4: Simplify right side
   391,275x = 386,798,790,692.25
5. Step 5: Solve for x
   x = 386,798,790,692.25/391,275
6. Step 6: Final answer
   x = 988,559.94