Finding the Fourth Proportional to 90.45, 124.74 and 57.69

Step by Step Solution

1. Step 1: Write the proportion equation
   90.45 : 124.74 = 57.69 : x
2. Step 2: Convert to fraction form
   90.45/124.74 = 57.69/x
3. Step 3: Cross multiply
   90.45x = 124.74 × 57.69
4. Step 4: Simplify right side
   90.45x = 7,196.25
5. Step 5: Solve for x
   x = 7,196.25/90.45
6. Step 6: Final answer
   x = 79.56