Finding the Fourth Proportional to 1,189.32, 1,642.02 and 816.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,189.32 : 1,642.02 = 816.20 : x
2. Step 2: Convert to fraction form
   1,189.32/1,642.02 = 816.20/x
3. Step 3: Cross multiply
   1,189.32x = 1,642.02 × 816.20
4. Step 4: Simplify right side
   1,189.32x = 1,340,216.72
5. Step 5: Solve for x
   x = 1,340,216.72/1,189.32
6. Step 6: Final answer
   x = 1,126.88