Finding the Fourth Proportional to 1,555.21, 2,146.05 and 917.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,555.21 : 2,146.05 = 917.05 : x
2. Step 2: Convert to fraction form
   1,555.21/2,146.05 = 917.05/x
3. Step 3: Cross multiply
   1,555.21x = 2,146.05 × 917.05
4. Step 4: Simplify right side
   1,555.21x = 1,968,035.15
5. Step 5: Solve for x
   x = 1,968,035.15/1,555.21
6. Step 6: Final answer
   x = 1,265.45