Finding the Fourth Proportional to 1,085.78, 1,630.30 and 1,069.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.78 : 1,630.30 = 1,069.58 : x
2. Step 2: Convert to fraction form
   1,085.78/1,630.30 = 1,069.58/x
3. Step 3: Cross multiply
   1,085.78x = 1,630.30 × 1,069.58
4. Step 4: Simplify right side
   1,085.78x = 1,743,736.27
5. Step 5: Solve for x
   x = 1,743,736.27/1,085.78
6. Step 6: Final answer
   x = 1,605.98