Finding the Fourth Proportional to 31,009.36, 42,720.60 and 21,561.52

Step by Step Solution

1. Step 1: Write the proportion equation
   31,009.36 : 42,720.60 = 21,561.52 : x
2. Step 2: Convert to fraction form
   31,009.36/42,720.60 = 21,561.52/x
3. Step 3: Cross multiply
   31,009.36x = 42,720.60 × 21,561.52
4. Step 4: Simplify right side
   31,009.36x = 921,121,071.31
5. Step 5: Solve for x
   x = 921,121,071.31/31,009.36
6. Step 6: Final answer
   x = 29,704.61