Finding the Fourth Proportional to 989.55, 1,477.86 and 841.72

Step by Step Solution

1. Step 1: Write the proportion equation
   989.55 : 1,477.86 = 841.72 : x
2. Step 2: Convert to fraction form
   989.55/1,477.86 = 841.72/x
3. Step 3: Cross multiply
   989.55x = 1,477.86 × 841.72
4. Step 4: Simplify right side
   989.55x = 1,243,944.32
5. Step 5: Solve for x
   x = 1,243,944.32/989.55
6. Step 6: Final answer
   x = 1,257.09