Finding the Fourth Proportional to 388.51, 535.69 and 290.10

Step by Step Solution

1. Step 1: Write the proportion equation
   388.51 : 535.69 = 290.10 : x
2. Step 2: Convert to fraction form
   388.51/535.69 = 290.10/x
3. Step 3: Cross multiply
   388.51x = 535.69 × 290.10
4. Step 4: Simplify right side
   388.51x = 155,401.72
5. Step 5: Solve for x
   x = 155,401.72/388.51
6. Step 6: Final answer
   x = 400.00