Finding the Third Proportional to 128,722.50 and 278,889

Step by Step Solution

1. Step 1: Write the proportion equation
   128,722.50 : 278,889 = 278,889 : x
2. Step 2: Convert to fraction form
   128,722.50/278,889 = 278,889/x
3. Step 3: Cross multiply
   128,722.50x = 278,889 × 278,889
4. Step 4: Simplify right side
   128,722.50x = 77,779,074,321
5. Step 5: Solve for x
   x = 77,779,074,321/128,722.50
6. Step 6: Final answer
   x = 604,238.38