Finding the Fourth Proportional to 1,390.02, 1,918.32 and 800.70

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.02 : 1,918.32 = 800.70 : x
2. Step 2: Convert to fraction form
   1,390.02/1,918.32 = 800.70/x
3. Step 3: Cross multiply
   1,390.02x = 1,918.32 × 800.70
4. Step 4: Simplify right side
   1,390.02x = 1,535,998.82
5. Step 5: Solve for x
   x = 1,535,998.82/1,390.02
6. Step 6: Final answer
   x = 1,105.02