Finding the Fourth Proportional to 1,167.89, 1,611.69 and 643.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,167.89 : 1,611.69 = 643.92 : x
2. Step 2: Convert to fraction form
   1,167.89/1,611.69 = 643.92/x
3. Step 3: Cross multiply
   1,167.89x = 1,611.69 × 643.92
4. Step 4: Simplify right side
   1,167.89x = 1,037,803.65
5. Step 5: Solve for x
   x = 1,037,803.65/1,167.89
6. Step 6: Final answer
   x = 888.61