Finding the Fourth Proportional to 1,009.80, 1,513.89 and 360.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,009.80 : 1,513.89 = 360.18 : x
2. Step 2: Convert to fraction form
   1,009.80/1,513.89 = 360.18/x
3. Step 3: Cross multiply
   1,009.80x = 1,513.89 × 360.18
4. Step 4: Simplify right side
   1,009.80x = 545,272.90
5. Step 5: Solve for x
   x = 545,272.90/1,009.80
6. Step 6: Final answer
   x = 539.98