Finding the Fourth Proportional to 1,308.50, 1,805.98 and 777.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,308.50 : 1,805.98 = 777.50 : x
2. Step 2: Convert to fraction form
   1,308.50/1,805.98 = 777.50/x
3. Step 3: Cross multiply
   1,308.50x = 1,805.98 × 777.50
4. Step 4: Simplify right side
   1,308.50x = 1,404,149.45
5. Step 5: Solve for x
   x = 1,404,149.45/1,308.50
6. Step 6: Final answer
   x = 1,073.10