Finding the Third Proportional to 216,759 and 287,689.50

Step by Step Solution

1. Step 1: Write the proportion equation
   216,759 : 287,689.50 = 287,689.50 : x
2. Step 2: Convert to fraction form
   216,759/287,689.50 = 287,689.50/x
3. Step 3: Cross multiply
   216,759x = 287,689.50 × 287,689.50
4. Step 4: Simplify right side
   216,759x = 82,765,248,410.25
5. Step 5: Solve for x
   x = 82,765,248,410.25/216,759
6. Step 6: Final answer
   x = 381,830.74