Finding the Third Proportional to 211,603 and 287,059.50

Step by Step Solution

1. Step 1: Write the proportion equation
   211,603 : 287,059.50 = 287,059.50 : x
2. Step 2: Convert to fraction form
   211,603/287,059.50 = 287,059.50/x
3. Step 3: Cross multiply
   211,603x = 287,059.50 × 287,059.50
4. Step 4: Simplify right side
   211,603x = 82,403,156,540.25
5. Step 5: Solve for x
   x = 82,403,156,540.25/211,603
6. Step 6: Final answer
   x = 389,423.39