Finding the Fourth Proportional to 2,085.21, 3,128.47 and 1,253.23

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.21 : 3,128.47 = 1,253.23 : x
2. Step 2: Convert to fraction form
   2,085.21/3,128.47 = 1,253.23/x
3. Step 3: Cross multiply
   2,085.21x = 3,128.47 × 1,253.23
4. Step 4: Simplify right side
   2,085.21x = 3,920,681.50
5. Step 5: Solve for x
   x = 3,920,681.50/2,085.21
6. Step 6: Final answer
   x = 1,880.23