Finding the Fourth Proportional to 10,938.63, 15,090.57 and 7,155.21

Step by Step Solution

1. Step 1: Write the proportion equation
   10,938.63 : 15,090.57 = 7,155.21 : x
2. Step 2: Convert to fraction form
   10,938.63/15,090.57 = 7,155.21/x
3. Step 3: Cross multiply
   10,938.63x = 15,090.57 × 7,155.21
4. Step 4: Simplify right side
   10,938.63x = 107,976,197.37
5. Step 5: Solve for x
   x = 107,976,197.37/10,938.63
6. Step 6: Final answer
   x = 9,871.09