Finding the Fourth Proportional to 1,579.55, 2,178.72 and 989.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,579.55 : 2,178.72 = 989.06 : x
2. Step 2: Convert to fraction form
   1,579.55/2,178.72 = 989.06/x
3. Step 3: Cross multiply
   1,579.55x = 2,178.72 × 989.06
4. Step 4: Simplify right side
   1,579.55x = 2,154,873.91
5. Step 5: Solve for x
   x = 2,154,873.91/1,579.55
6. Step 6: Final answer
   x = 1,364.24