Finding the Third Proportional to 211,605 and 287,061

Step by Step Solution

1. Step 1: Write the proportion equation
   211,605 : 287,061 = 287,061 : x
2. Step 2: Convert to fraction form
   211,605/287,061 = 287,061/x
3. Step 3: Cross multiply
   211,605x = 287,061 × 287,061
4. Step 4: Simplify right side
   211,605x = 82,404,017,721
5. Step 5: Solve for x
   x = 82,404,017,721/211,605
6. Step 6: Final answer
   x = 389,423.77