Finding the Fourth Proportional to 1,069.02, 1,602.72 and 419.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,069.02 : 1,602.72 = 419.40 : x
2. Step 2: Convert to fraction form
   1,069.02/1,602.72 = 419.40/x
3. Step 3: Cross multiply
   1,069.02x = 1,602.72 × 419.40
4. Step 4: Simplify right side
   1,069.02x = 672,180.77
5. Step 5: Solve for x
   x = 672,180.77/1,069.02
6. Step 6: Final answer
   x = 628.78