Finding the Fourth Proportional to 1,189.08, 1,640.53 and 691.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,189.08 : 1,640.53 = 691.31 : x
2. Step 2: Convert to fraction form
   1,189.08/1,640.53 = 691.31/x
3. Step 3: Cross multiply
   1,189.08x = 1,640.53 × 691.31
4. Step 4: Simplify right side
   1,189.08x = 1,134,111.34
5. Step 5: Solve for x
   x = 1,134,111.34/1,189.08
6. Step 6: Final answer
   x = 953.77