Finding the Fourth Proportional to 42,931.22, 64,393.58 and 21,858.05

Step by Step Solution

1. Step 1: Write the proportion equation
   42,931.22 : 64,393.58 = 21,858.05 : x
2. Step 2: Convert to fraction form
   42,931.22/64,393.58 = 21,858.05/x
3. Step 3: Cross multiply
   42,931.22x = 64,393.58 × 21,858.05
4. Step 4: Simplify right side
   42,931.22x = 1,407,518,306.95
5. Step 5: Solve for x
   x = 1,407,518,306.95/42,931.22
6. Step 6: Final answer
   x = 32,785.43