Finding the Fourth Proportional to 1,173.08, 1,618.86 and 641.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,173.08 : 1,618.86 = 641.98 : x
2. Step 2: Convert to fraction form
   1,173.08/1,618.86 = 641.98/x
3. Step 3: Cross multiply
   1,173.08x = 1,618.86 × 641.98
4. Step 4: Simplify right side
   1,173.08x = 1,039,275.74
5. Step 5: Solve for x
   x = 1,039,275.74/1,173.08
6. Step 6: Final answer
   x = 885.94