Finding the Fourth Proportional to 1,167.80, 1,611.50 and 643.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,167.80 : 1,611.50 = 643.83 : x
2. Step 2: Convert to fraction form
   1,167.80/1,611.50 = 643.83/x
3. Step 3: Cross multiply
   1,167.80x = 1,611.50 × 643.83
4. Step 4: Simplify right side
   1,167.80x = 1,037,528.83
5. Step 5: Solve for x
   x = 1,037,528.83/1,167.80
6. Step 6: Final answer
   x = 888.45