Finding the Third Proportional to 316,779.75 and 689,328

Step by Step Solution

1. Step 1: Write the proportion equation
   316,779.75 : 689,328 = 689,328 : x
2. Step 2: Convert to fraction form
   316,779.75/689,328 = 689,328/x
3. Step 3: Cross multiply
   316,779.75x = 689,328 × 689,328
4. Step 4: Simplify right side
   316,779.75x = 475,173,091,584
5. Step 5: Solve for x
   x = 475,173,091,584/316,779.75
6. Step 6: Final answer
   x = 1,500,010.94