Finding the Fourth Proportional to 1,691.03, 2,535.59 and 520.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,691.03 : 2,535.59 = 520.72 : x
2. Step 2: Convert to fraction form
   1,691.03/2,535.59 = 520.72/x
3. Step 3: Cross multiply
   1,691.03x = 2,535.59 × 520.72
4. Step 4: Simplify right side
   1,691.03x = 1,320,327.39
5. Step 5: Solve for x
   x = 1,320,327.39/1,691.03
6. Step 6: Final answer
   x = 780.78