Finding the Fourth Proportional to 39,870.18, 55,018.67 and 21,961.67

Step by Step Solution

1. Step 1: Write the proportion equation
   39,870.18 : 55,018.67 = 21,961.67 : x
2. Step 2: Convert to fraction form
   39,870.18/55,018.67 = 21,961.67/x
3. Step 3: Cross multiply
   39,870.18x = 55,018.67 × 21,961.67
4. Step 4: Simplify right side
   39,870.18x = 1,208,301,489.48
5. Step 5: Solve for x
   x = 1,208,301,489.48/39,870.18
6. Step 6: Final answer
   x = 30,305.90