Finding the Fourth Proportional to 1,019.42, 1,407.60 and 665.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.42 : 1,407.60 = 665.58 : x
2. Step 2: Convert to fraction form
   1,019.42/1,407.60 = 665.58/x
3. Step 3: Cross multiply
   1,019.42x = 1,407.60 × 665.58
4. Step 4: Simplify right side
   1,019.42x = 936,870.41
5. Step 5: Solve for x
   x = 936,870.41/1,019.42
6. Step 6: Final answer
   x = 919.03