Finding the Fourth Proportional to 2,085.21, 3,127.86 and 989.69

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.21 : 3,127.86 = 989.69 : x
2. Step 2: Convert to fraction form
   2,085.21/3,127.86 = 989.69/x
3. Step 3: Cross multiply
   2,085.21x = 3,127.86 × 989.69
4. Step 4: Simplify right side
   2,085.21x = 3,095,596.12
5. Step 5: Solve for x
   x = 3,095,596.12/2,085.21
6. Step 6: Final answer
   x = 1,484.55