Finding the Third Proportional to 121,216.50 and 257,985

Step by Step Solution

1. Step 1: Write the proportion equation
   121,216.50 : 257,985 = 257,985 : x
2. Step 2: Convert to fraction form
   121,216.50/257,985 = 257,985/x
3. Step 3: Cross multiply
   121,216.50x = 257,985 × 257,985
4. Step 4: Simplify right side
   121,216.50x = 66,556,260,225
5. Step 5: Solve for x
   x = 66,556,260,225/121,216.50
6. Step 6: Final answer
   x = 549,069.31