Finding the Fourth Proportional to 42,977.16, 64,478.94 and 20,516.50

Step by Step Solution

1. Step 1: Write the proportion equation
   42,977.16 : 64,478.94 = 20,516.50 : x
2. Step 2: Convert to fraction form
   42,977.16/64,478.94 = 20,516.50/x
3. Step 3: Cross multiply
   42,977.16x = 64,478.94 × 20,516.50
4. Step 4: Simplify right side
   42,977.16x = 1,322,882,172.51
5. Step 5: Solve for x
   x = 1,322,882,172.51/42,977.16
6. Step 6: Final answer
   x = 30,781.05