Finding the Fourth Proportional to 1,145.86, 1,580.73 and 679.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.86 : 1,580.73 = 679.78 : x
2. Step 2: Convert to fraction form
   1,145.86/1,580.73 = 679.78/x
3. Step 3: Cross multiply
   1,145.86x = 1,580.73 × 679.78
4. Step 4: Simplify right side
   1,145.86x = 1,074,548.64
5. Step 5: Solve for x
   x = 1,074,548.64/1,145.86
6. Step 6: Final answer
   x = 937.77