Finding the Fourth Proportional to 1,008.30, 1,513.20 and 521.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,008.30 : 1,513.20 = 521.10 : x
2. Step 2: Convert to fraction form
   1,008.30/1,513.20 = 521.10/x
3. Step 3: Cross multiply
   1,008.30x = 1,513.20 × 521.10
4. Step 4: Simplify right side
   1,008.30x = 788,528.52
5. Step 5: Solve for x
   x = 788,528.52/1,008.30
6. Step 6: Final answer
   x = 782.04