Finding the Fourth Proportional to 42.74, 64.12 and 42.15

Step by Step Solution

1. Step 1: Write the proportion equation
   42.74 : 64.12 = 42.15 : x
2. Step 2: Convert to fraction form
   42.74/64.12 = 42.15/x
3. Step 3: Cross multiply
   42.74x = 64.12 × 42.15
4. Step 4: Simplify right side
   42.74x = 2,702.51
5. Step 5: Solve for x
   x = 2,702.51/42.74
6. Step 6: Final answer
   x = 63.22