 This is the video for practice problem one, and we are asked to find the exact surface area of this cylinder. Remember, I always like to start these problems by writing out the formula and identifying the bases. This formula for a cylinder is similar to that of a prism, two times B plus the perimeter times the height. But remember when we're working with cylinders, we're going to change that B because B represents the area of my base, and since my base is a circle, the area of the circle becomes pi r squared. P represents the perimeter of my base and because my base is a circle, that's represented by the circumference of the circle. The perimeter of a circle is the same as the circumference of the circle, and that's 2 pi r. So I'm going to use this formula that's derived from the prison formula for a prism and I would recommend that you write off to the side the values that we're going to need to plug into the formula. All I need for this is r and h. Keep in mind that we're asked to find the exact surface area, so we're going to leave it in pi form and our final answer will have pi in it. This is a pretty simple problem because if we're just asked to find r and h, those are given outright to us and we don't have to do any calculations to find them. R is the radius of my base, the radius of the circle, and that's given to us as 5. Keep in mind that if we're given the diameter of the circle, we're just going to have to cut that in half, but this one is just giving us the plain old radius and h is the height of my cylinder. That's the distance between the bases and that's given to us outright. So we just have to go ahead and plug this into our formula and simplify it. We're going to leave it in pi form, so I'm going to leave the pi as it is and just plug in the values. The r is 5 and then 2 pi times the radius times the height. And this is the part you just need to be careful of simplifying. We're going to simplify each of these separately and then add them together. 2 times pi times 5 squared. I'm going to square that first and then 2 times 25. I'm going to leave it in pi form, so I'm just going to simplify that as 50 pi. The second term, I'm going to just multiply each of the numbers. 2 times 5 times 8, 2 times 5 is 10 and 10 times 8 is 80. So that second term simplifies to 80 pi and because both of those terms have pi in it, my final answer is going to be 130 pi. Make sure you label it correctly. It's surface area and no measurement is given, so I'm going to label that as units squared and that's my final answer.