Finding the Fourth Proportional to 1,189.80, 1,780.38 and 1,005.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,189.80 : 1,780.38 = 1,005.12 : x
2. Step 2: Convert to fraction form
   1,189.80/1,780.38 = 1,005.12/x
3. Step 3: Cross multiply
   1,189.80x = 1,780.38 × 1,005.12
4. Step 4: Simplify right side
   1,189.80x = 1,789,495.55
5. Step 5: Solve for x
   x = 1,789,495.55/1,189.80
6. Step 6: Final answer
   x = 1,504.03