Finding the Fourth Proportional to 1,388.85, 1,916.72 and 829.35

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.85 : 1,916.72 = 829.35 : x
2. Step 2: Convert to fraction form
   1,388.85/1,916.72 = 829.35/x
3. Step 3: Cross multiply
   1,388.85x = 1,916.72 × 829.35
4. Step 4: Simplify right side
   1,388.85x = 1,589,623.51
5. Step 5: Solve for x
   x = 1,589,623.51/1,388.85
6. Step 6: Final answer
   x = 1,144.56