Finding the Fourth Proportional to 769.42, 1,061.81 and 420.10

Step by Step Solution

1. Step 1: Write the proportion equation
   769.42 : 1,061.81 = 420.10 : x
2. Step 2: Convert to fraction form
   769.42/1,061.81 = 420.10/x
3. Step 3: Cross multiply
   769.42x = 1,061.81 × 420.10
4. Step 4: Simplify right side
   769.42x = 446,066.38
5. Step 5: Solve for x
   x = 446,066.38/769.42
6. Step 6: Final answer
   x = 579.74