Finding the Fourth Proportional to 213,443.12, 320,199.42 and 99,704.63

Step by Step Solution

1. Step 1: Write the proportion equation
   213,443.12 : 320,199.42 = 99,704.63 : x
2. Step 2: Convert to fraction form
   213,443.12/320,199.42 = 99,704.63/x
3. Step 3: Cross multiply
   213,443.12x = 320,199.42 × 99,704.63
4. Step 4: Simplify right side
   213,443.12x = 31,925,364,697.31
5. Step 5: Solve for x
   x = 31,925,364,697.31/213,443.12
6. Step 6: Final answer
   x = 149,573.17