Finding the Fourth Proportional to 1,720.24, 2,578.56 and 1,308.51

Step by Step Solution

1. Step 1: Write the proportion equation
   1,720.24 : 2,578.56 = 1,308.51 : x
2. Step 2: Convert to fraction form
   1,720.24/2,578.56 = 1,308.51/x
3. Step 3: Cross multiply
   1,720.24x = 2,578.56 × 1,308.51
4. Step 4: Simplify right side
   1,720.24x = 3,374,071.55
5. Step 5: Solve for x
   x = 3,374,071.55/1,720.24
6. Step 6: Final answer
   x = 1,961.40