Finding the Third Proportional to 311,172 and 678,655.50

Step by Step Solution

1. Step 1: Write the proportion equation
   311,172 : 678,655.50 = 678,655.50 : x
2. Step 2: Convert to fraction form
   311,172/678,655.50 = 678,655.50/x
3. Step 3: Cross multiply
   311,172x = 678,655.50 × 678,655.50
4. Step 4: Simplify right side
   311,172x = 460,573,287,680.25
5. Step 5: Solve for x
   x = 460,573,287,680.25/311,172
6. Step 6: Final answer
   x = 1,480,124.46