Finding the Fourth Proportional to 1,111.24, 1,533.54 and 645.64

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.24 : 1,533.54 = 645.64 : x
2. Step 2: Convert to fraction form
   1,111.24/1,533.54 = 645.64/x
3. Step 3: Cross multiply
   1,111.24x = 1,533.54 × 645.64
4. Step 4: Simplify right side
   1,111.24x = 990,114.77
5. Step 5: Solve for x
   x = 990,114.77/1,111.24
6. Step 6: Final answer
   x = 891.00