Finding the Fourth Proportional to 7,820.40, 10,864.72 and 7,748.40

Step by Step Solution

1. Step 1: Write the proportion equation
   7,820.40 : 10,864.72 = 7,748.40 : x
2. Step 2: Convert to fraction form
   7,820.40/10,864.72 = 7,748.40/x
3. Step 3: Cross multiply
   7,820.40x = 10,864.72 × 7,748.40
4. Step 4: Simplify right side
   7,820.40x = 84,184,196.45
5. Step 5: Solve for x
   x = 84,184,196.45/7,820.40
6. Step 6: Final answer
   x = 10,764.69