Finding the Fourth Proportional to 1,128.12, 1,690.56 and 510.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.12 : 1,690.56 = 510.30 : x
2. Step 2: Convert to fraction form
   1,128.12/1,690.56 = 510.30/x
3. Step 3: Cross multiply
   1,128.12x = 1,690.56 × 510.30
4. Step 4: Simplify right side
   1,128.12x = 862,692.77
5. Step 5: Solve for x
   x = 862,692.77/1,128.12
6. Step 6: Final answer
   x = 764.72