Finding the Third Proportional to 869.63 and 1,921.50

Step by Step Solution

1. Step 1: Write the proportion equation
   869.63 : 1,921.50 = 1,921.50 : x
2. Step 2: Convert to fraction form
   869.63/1,921.50 = 1,921.50/x
3. Step 3: Cross multiply
   869.63x = 1,921.50 × 1,921.50
4. Step 4: Simplify right side
   869.63x = 3,692,162.25
5. Step 5: Solve for x
   x = 3,692,162.25/869.63
6. Step 6: Final answer
   x = 4,245.69