Finding the Fourth Proportional to 1,355.32, 1,870.86 and 913.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,355.32 : 1,870.86 = 913.60 : x
2. Step 2: Convert to fraction form
   1,355.32/1,870.86 = 913.60/x
3. Step 3: Cross multiply
   1,355.32x = 1,870.86 × 913.60
4. Step 4: Simplify right side
   1,355.32x = 1,709,217.70
5. Step 5: Solve for x
   x = 1,709,217.70/1,355.32
6. Step 6: Final answer
   x = 1,261.12