Finding the Fourth Proportional to 1,290.50, 1,936.18 and 510.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.50 : 1,936.18 = 510.72 : x
2. Step 2: Convert to fraction form
   1,290.50/1,936.18 = 510.72/x
3. Step 3: Cross multiply
   1,290.50x = 1,936.18 × 510.72
4. Step 4: Simplify right side
   1,290.50x = 988,840.51
5. Step 5: Solve for x
   x = 988,840.51/1,290.50
6. Step 6: Final answer
   x = 766.25