Finding the Fourth Proportional to 1,145.08, 1,580.18 and 621.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.08 : 1,580.18 = 621.10 : x
2. Step 2: Convert to fraction form
   1,145.08/1,580.18 = 621.10/x
3. Step 3: Cross multiply
   1,145.08x = 1,580.18 × 621.10
4. Step 4: Simplify right side
   1,145.08x = 981,449.80
5. Step 5: Solve for x
   x = 981,449.80/1,145.08
6. Step 6: Final answer
   x = 857.10