SA=2pi(4 squared) + 2pi (4)(20)

To simplify this expression, let's break it down step by step:

The given expression is:
SA = 2π(4^2) + 2π(4)(20)

Step 1: Calculate the term 2π(4^2)
First, square the value of 4:
4^2 = 4 * 4 = 16

Now, multiply the result by 2π:
2π * 16 = 32π

So, the first term is 32π.

Step 2: Calculate the term 2π(4)(20)
Multiply the numbers inside the parentheses:
4 * 20 = 80

Now, multiply the result by 2π:
2π * 80 = 160π

So, the second term is 160π.

Step 3: Add the two terms together
We have the first term as 32π and the second term as 160π.
To get the sum, add them together:
32π + 160π = 192π

Thus, the simplified expression is:
SA = 192π

Therefore, the surface area (SA) is equal to 192π.