Finding the Fourth Proportional to 13,091.90, 18,066.78 and 7,123.55

Step by Step Solution

1. Step 1: Write the proportion equation
   13,091.90 : 18,066.78 = 7,123.55 : x
2. Step 2: Convert to fraction form
   13,091.90/18,066.78 = 7,123.55/x
3. Step 3: Cross multiply
   13,091.90x = 18,066.78 × 7,123.55
4. Step 4: Simplify right side
   13,091.90x = 128,699,520.34
5. Step 5: Solve for x
   x = 128,699,520.34/13,091.90
6. Step 6: Final answer
   x = 9,830.47