Finding the Fourth Proportional to 1,381.51, 2,072.55 and 765.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.51 : 2,072.55 = 765.76 : x
2. Step 2: Convert to fraction form
   1,381.51/2,072.55 = 765.76/x
3. Step 3: Cross multiply
   1,381.51x = 2,072.55 × 765.76
4. Step 4: Simplify right side
   1,381.51x = 1,587,075.89
5. Step 5: Solve for x
   x = 1,587,075.89/1,381.51
6. Step 6: Final answer
   x = 1,148.80