Finding the Fourth Proportional to 1,390.23, 1,917.91 and 917.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.23 : 1,917.91 = 917.52 : x
2. Step 2: Convert to fraction form
   1,390.23/1,917.91 = 917.52/x
3. Step 3: Cross multiply
   1,390.23x = 1,917.91 × 917.52
4. Step 4: Simplify right side
   1,390.23x = 1,759,720.78
5. Step 5: Solve for x
   x = 1,759,720.78/1,390.23
6. Step 6: Final answer
   x = 1,265.78