Finding the Fourth Proportional to 1,030.72, 1,545.72 and 445.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,030.72 : 1,545.72 = 445.78 : x
2. Step 2: Convert to fraction form
   1,030.72/1,545.72 = 445.78/x
3. Step 3: Cross multiply
   1,030.72x = 1,545.72 × 445.78
4. Step 4: Simplify right side
   1,030.72x = 689,051.06
5. Step 5: Solve for x
   x = 689,051.06/1,030.72
6. Step 6: Final answer
   x = 668.51