Finding the Fourth Proportional to 1,100.21, 1,648.02 and 515.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,100.21 : 1,648.02 = 515.72 : x
2. Step 2: Convert to fraction form
   1,100.21/1,648.02 = 515.72/x
3. Step 3: Cross multiply
   1,100.21x = 1,648.02 × 515.72
4. Step 4: Simplify right side
   1,100.21x = 849,908.63
5. Step 5: Solve for x
   x = 849,908.63/1,100.21
6. Step 6: Final answer
   x = 772.49