Finding the Fourth Proportional to 1,167.09, 1,610.59 and 643.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,167.09 : 1,610.59 = 643.12 : x
2. Step 2: Convert to fraction form
   1,167.09/1,610.59 = 643.12/x
3. Step 3: Cross multiply
   1,167.09x = 1,610.59 × 643.12
4. Step 4: Simplify right side
   1,167.09x = 1,035,799.43
5. Step 5: Solve for x
   x = 1,035,799.43/1,167.09
6. Step 6: Final answer
   x = 887.51