Finding the Fourth Proportional to 1,176.72, 1,623.80 and 645.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,176.72 : 1,623.80 = 645.50 : x
2. Step 2: Convert to fraction form
   1,176.72/1,623.80 = 645.50/x
3. Step 3: Cross multiply
   1,176.72x = 1,623.80 × 645.50
4. Step 4: Simplify right side
   1,176.72x = 1,048,162.90
5. Step 5: Solve for x
   x = 1,048,162.90/1,176.72
6. Step 6: Final answer
   x = 890.75