Add all of the sides of the base to find the perimeter.
Multiply the perimeter by the height of the shape. Remember the height is the distance between the two bases and that the 3-dimensional shape might not be oriented vertically.
Identify the units of which with the sides are labeled. Square this unit to get the unit for the answer. For example, if the height is labeled in cm, you would write the answer with cm^2. Do the same for any other type of shape.
Identify the radius of the base. If given the diameter instead, divide by 2 to find the radius.
Multiply the radius by 2 pi to find the circumference of the base.
Multiply the circumference of the base from Step 2 with the height of the cylinder to get the lateral area of the cylinder.
Find the radius of the base.
Identify the slant height - the height from the bottom edge of the base to the peak of the cone. If given the true height instead, draw a right triangle down the middle of the cone and use the Pythagorean theorem to find the slant height.
Multiply pi, the radius, and the slant height (symbolized with l) to find the lateral area of the cone.
Add all the sides of the base to find the perimeter.
Multiply the perimeter by 1/2.
Identify the height (distance between the two bases). Multiply the result from Step 2 by the height to get the lateral area of the pyramid.