Finding the Fourth Proportional to 2,113.82, 3,171.63 and 816.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,113.82 : 3,171.63 = 816.20 : x
2. Step 2: Convert to fraction form
   2,113.82/3,171.63 = 816.20/x
3. Step 3: Cross multiply
   2,113.82x = 3,171.63 × 816.20
4. Step 4: Simplify right side
   2,113.82x = 2,588,668.55
5. Step 5: Solve for x
   x = 2,588,668.55/2,113.82
6. Step 6: Final answer
   x = 1,224.64