Finding the Fourth Proportional to 1,238.53, 1,859.34 and 770.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.53 : 1,859.34 = 770.69 : x
2. Step 2: Convert to fraction form
   1,238.53/1,859.34 = 770.69/x
3. Step 3: Cross multiply
   1,238.53x = 1,859.34 × 770.69
4. Step 4: Simplify right side
   1,238.53x = 1,432,974.74
5. Step 5: Solve for x
   x = 1,432,974.74/1,238.53
6. Step 6: Final answer
   x = 1,157.00