Finding the Fourth Proportional to 21,012.51, 31,517.86 and 5,217.17

Step by Step Solution

1. Step 1: Write the proportion equation
   21,012.51 : 31,517.86 = 5,217.17 : x
2. Step 2: Convert to fraction form
   21,012.51/31,517.86 = 5,217.17/x
3. Step 3: Cross multiply
   21,012.51x = 31,517.86 × 5,217.17
4. Step 4: Simplify right side
   21,012.51x = 164,434,094.42
5. Step 5: Solve for x
   x = 164,434,094.42/21,012.51
6. Step 6: Final answer
   x = 7,825.53