Finding the Fourth Proportional to 1,167.42, 1,610.96 and 643.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,167.42 : 1,610.96 = 643.50 : x
2. Step 2: Convert to fraction form
   1,167.42/1,610.96 = 643.50/x
3. Step 3: Cross multiply
   1,167.42x = 1,610.96 × 643.50
4. Step 4: Simplify right side
   1,167.42x = 1,036,652.76
5. Step 5: Solve for x
   x = 1,036,652.76/1,167.42
6. Step 6: Final answer
   x = 887.99