Finding the Fourth Proportional to 1,188.69, 1,636.20 and 856.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,188.69 : 1,636.20 = 856.59 : x
2. Step 2: Convert to fraction form
   1,188.69/1,636.20 = 856.59/x
3. Step 3: Cross multiply
   1,188.69x = 1,636.20 × 856.59
4. Step 4: Simplify right side
   1,188.69x = 1,401,552.56
5. Step 5: Solve for x
   x = 1,401,552.56/1,188.69
6. Step 6: Final answer
   x = 1,179.07