Finding the Fourth Proportional to 1,339.87, 1,848.40 and 816.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,339.87 : 1,848.40 = 816.21 : x
2. Step 2: Convert to fraction form
   1,339.87/1,848.40 = 816.21/x
3. Step 3: Cross multiply
   1,339.87x = 1,848.40 × 816.21
4. Step 4: Simplify right side
   1,339.87x = 1,508,682.56
5. Step 5: Solve for x
   x = 1,508,682.56/1,339.87
6. Step 6: Final answer
   x = 1,125.99