All SAT II Math I Resources
Example Questions
Example Question #12 : Cones
What is the surface area of a cone with a radius of 6 in and a height of 8 in?
36π in2
60π in2
66π in2
112π in2
96π in2
96π in2
Find the slant height of the cone using the Pythagorean theorem: r2 + h2 = s2 resulting in 62 + 82 = s2 leading to s2 = 100 or s = 10 in
SA = πrs + πr2 = π(6)(10) + π(6)2 = 60π + 36π = 96π in2
60π in2 is the area of the cone without the base.
36π in2 is the area of the base only.
Example Question #1 : How To Find The Surface Area Of A Cone
Use the following formula to answer the question.
The slant height of a right circular cone is . The radius is , and the height is . Determine the surface area of the cone.
Notice that the height of the cone is not needed to answer this question and is simply extraneous information. We are told that the radius is , and the slant height is .
First plug these numbers into the equation provided.
Then simplify by combining like terms.
Example Question #11 : Surface Area
The slant height of a cone is ; the diameter of its base is one-fifth its slant height. Give the surface area of the cone in terms of .
The formula for the surface area of a cone with base of radius and slant height is
.
The diameter of the base is ; the radius is half this, so
Substitute in the surface area formula:
Example Question #1 : How To Find The Surface Area Of A Cone
The radius of the base of a cone is ; its slant height is two-thirds of the diameter of that base. Give its surface area in terms of .
The formula for the surface area of a cone with base of radius and slant height is
.
The diameter of the base is twice radius , or , and its slant height is two-thirds of this diameter, which is . Substitute this for in the formula:
Example Question #2 : How To Find The Surface Area Of A Cone
The radius of the base of a cone is ; its height is twice of the diameter of that base. Give its surface area in terms of .
The formula for the surface area of a cone with base of radius and slant height is
.
The base has radius and diameter . The height is twice the diamter, which is . Its slant height can be calculated using the Pythagorean Theorem:
Substitute for in the surface area formula:
Example Question #122 : Geometry
The height of a cone is ; the diameter of its base is twice the height. Give its surface area in terms of .
The formula for the surface area of a cone with base of radius and slant height is
.
The diameter of the base is twice the height, which is ; the radius is half this, which is .
The slant height can be calculated using the Pythagorean Theorem:
Substitute for and for in the surface area formula:
Example Question #123 : Geometry
The circumference of the base of a cone is 80; the slant height of the cone is equal to twice the diameter of the base. Give the surface area of the cone (nearest whole number).
The formula for the surface area of a cone with base of radius and slant height is
.
The slant height is twice the diameter, or, equivalently, four times the radius, so
and
The radius of the base is the circumference divided by , which is
Substitute:
Example Question #2 : How To Find The Surface Area Of A Cone
The circumference of the base of a cone is 100; the height of the cone is equal to the diameter of the base. Give the surface area of the cone (nearest whole number).
The formula for the surface area of a cone with base of radius and slant height is
.
The diameter of the base is the circumference divided by , which is
This is also the height .
The radius is half this, or
The slant height can be found by way of the Pythagorean Theorem:
Substitute in the surface area formula:
Example Question #21 : Surface Area
If a cone were unfurled into a 2-dimensional figure. The lateral area of the cone would look most like which figure?
Circle
Triangle
Rectangle
Sector of a Circle
Sector of a Circle
When creating a net image of a 3D figure - one imagines it is made of paper and is unfurled into its' 2D form. The lateral portion of the cone cone would be unfurled into the image of a Sector of a Circle. To include the full surface area of the cone a circle is included to form the base of the cone as in the figure below. The lateral area portion is the top part of the figure below.
Example Question #121 : Geometry
Find the surface area of a cube with side length of 6in.
A cube is made up of 6 identical sides. Find the area of one side and multiplying it by 6 will result in the surface area of a cube.
a is the side length, in this case 6in.
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