Finding the Third Proportional to 216,720 and 287,563.50

Step by Step Solution

1. Step 1: Write the proportion equation
   216,720 : 287,563.50 = 287,563.50 : x
2. Step 2: Convert to fraction form
   216,720/287,563.50 = 287,563.50/x
3. Step 3: Cross multiply
   216,720x = 287,563.50 × 287,563.50
4. Step 4: Simplify right side
   216,720x = 82,692,766,532.25
5. Step 5: Solve for x
   x = 82,692,766,532.25/216,720
6. Step 6: Final answer
   x = 381,565.00