Finding the Fourth Proportional to 1,038.56, 1,433.72 and 645.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,038.56 : 1,433.72 = 645.83 : x
2. Step 2: Convert to fraction form
   1,038.56/1,433.72 = 645.83/x
3. Step 3: Cross multiply
   1,038.56x = 1,433.72 × 645.83
4. Step 4: Simplify right side
   1,038.56x = 925,928.99
5. Step 5: Solve for x
   x = 925,928.99/1,038.56
6. Step 6: Final answer
   x = 891.55