Finding the Fourth Proportional to 91,128.69, 136,688.18 and 31,970.34

Step by Step Solution

1. Step 1: Write the proportion equation
   91,128.69 : 136,688.18 = 31,970.34 : x
2. Step 2: Convert to fraction form
   91,128.69/136,688.18 = 31,970.34/x
3. Step 3: Cross multiply
   91,128.69x = 136,688.18 × 31,970.34
4. Step 4: Simplify right side
   91,128.69x = 4,369,967,428.73
5. Step 5: Solve for x
   x = 4,369,967,428.73/91,128.69
6. Step 6: Final answer
   x = 47,953.80