Finding the Fourth Proportional to 1,085.87, 1,624.73 and 645.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,085.87 : 1,624.73 = 645.50 : x
2. Step 2: Convert to fraction form
   1,085.87/1,624.73 = 645.50/x
3. Step 3: Cross multiply
   1,085.87x = 1,624.73 × 645.50
4. Step 4: Simplify right side
   1,085.87x = 1,048,764.05
5. Step 5: Solve for x
   x = 1,048,764.05/1,085.87
6. Step 6: Final answer
   x = 965.83