Finding the Fourth Proportional to 1,111.27, 1,533.31 and 645.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.27 : 1,533.31 = 645.25 : x
2. Step 2: Convert to fraction form
   1,111.27/1,533.31 = 645.25/x
3. Step 3: Cross multiply
   1,111.27x = 1,533.31 × 645.25
4. Step 4: Simplify right side
   1,111.27x = 989,368.28
5. Step 5: Solve for x
   x = 989,368.28/1,111.27
6. Step 6: Final answer
   x = 890.30