Finding the Fourth Proportional to 1,019.60, 1,407.06 and 553.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.60 : 1,407.06 = 553.86 : x
2. Step 2: Convert to fraction form
   1,019.60/1,407.06 = 553.86/x
3. Step 3: Cross multiply
   1,019.60x = 1,407.06 × 553.86
4. Step 4: Simplify right side
   1,019.60x = 779,314.25
5. Step 5: Solve for x
   x = 779,314.25/1,019.60
6. Step 6: Final answer
   x = 764.33