Finding the Fourth Proportional to 9,191.51, 12,670.69 and 7,172.64

Step by Step Solution

1. Step 1: Write the proportion equation
   9,191.51 : 12,670.69 = 7,172.64 : x
2. Step 2: Convert to fraction form
   9,191.51/12,670.69 = 7,172.64/x
3. Step 3: Cross multiply
   9,191.51x = 12,670.69 × 7,172.64
4. Step 4: Simplify right side
   9,191.51x = 90,882,297.92
5. Step 5: Solve for x
   x = 90,882,297.92/9,191.51
6. Step 6: Final answer
   x = 9,887.64