All SAT Math Resources
Example Questions
Example Question #811 : Geometry
A sphere fits inside of a cube so that its surface barely touches each side of the cube at any given time. If the volume of the box is 27 cubic centimeters, then what is the volume of the sphere?
None of the given answers.
If the volume of the cube is 27 cubic centimeters, then its height, width, and depth are all 3cm. Since the sphere fits perfectly in the cube, then the sphere's diameter is also 3. This means that its radius is .
Substitute this radius value into the equation for the volume of a sphere:
Example Question #17 : How To Find The Volume Of A Sphere
The surface area of a sphere is 100. Give its volume.
The surface area of a sphere is equal to
,
where is the radius.
Setting and solving for :
Applying the Quotient of Radicals Rule:
The volume of the sphere can be determined from the radius using the formula
,
so, setting :
Applying the Quotient of Radicals Rule:
Rationalizing the denominator:
Example Question #812 : Geometry
is a point on a sphere, and is the point on the sphere farthest from . The shortest curve from to that is completely on the sphere is in length.
Give the volume of the sphere.
The figure referenced is below. is the center of the sphere.
The shortest curve connecting to its opposite point is a semicircle. Also, is a diameter of the sphere, and and are radii.
Given radius , a semicircle has length
Setting and solving for :
.
The volume of a sphere, given its radius , is
.
Setting :
Example Question #121 : Solid Geometry
Find the volume of a sphere whose diameter is 10cm.
Radius is half of the diameter. Half of 10cm is 5cm.
Example Question #43 : Spheres
The radius of the sphere shown here is long. What is its volume?
The formula for the volume of a sphere given its radius is
The radius is stated to be long; hence, we can calculate the sphere's volume by substituting this value for into the formula, as shown:
Hence, the volume of the sphere is
Example Question #1951 : Hspt Mathematics
The volume of a cylinder is 36π. If the cylinder’s height is 4, what is the cylinder’s diameter?
4
9
6
3
12
6
Volume of a cylinder? V = πr2h. Rewritten as a diameter equation, this is:
V = π(d/2)2h = πd2h/4
Sub in h and V: 36p = πd2(4)/4 so 36p = πd2
Thus d = 6
Example Question #1 : How To Find The Volume Of A Cylinder
A cylinder has a height of 5 inches and a radius of 3 inches. Find the lateral area of the cylinder.
8π
15π
45π
24π
30π
30π
LA = 2π(r)(h) = 2π(3)(5) = 30π
Example Question #1 : Cylinders
A cylinder has a volume of 20. If the radius doubles, what is the new volume?
100
20
60
80
40
80
The equation for the volume of the cylinder is πr2h. When the radius doubles (r becomes 2r) you get π(2r)2h = 4πr2h. So when the radius doubles, the volume quadruples, giving a new volume of 80.
Example Question #1 : How To Find The Volume Of A Cylinder
A cylinder has a height that is three times as long as its radius. If the lateral surface area of the cylinder is 54π square units, then what is its volume in cubic units?
81π
9π
54π
243π
27π
81π
Let us call r the radius and h the height of the cylinder. We are told that the height is three times the radius, which we can represent as h = 3r.
We are also told that the lateral surface area is equal to 54π. The lateral surface area is the surface area that does not include the bases. The formula for the lateral surface area is equal to the circumference of the cylinder times its height, or 2πrh. We set this equal to 54π,
2πrh = 54π
Now we substitute 3r in for h.
2πr(3r) = 54π
6πr2 = 54π
Divide by 6π
r2 = 9.
Take the square root.
r = 3.
h = 3r = 3(3) = 9.
Now that we have the radius and the height of the cylinder, we can find its volume, which is given by πr2h.
V = πr2h
V = π(3)2(9) = 81π
The answer is 81π.
Example Question #1 : How To Find The Volume Of A Cylinder
What is the volume of a hollow cylinder whose inner radius is 2 cm and outer radius is 4 cm, with a height of 5 cm?
80π cm3
100π cm3
60π cm3
50π cm3
20π cm3
60π cm3
The volume is found by subtracting the inner cylinder from the outer cylinder as given by V = πrout2 h – πrin2 h. The area of the cylinder using the outer radius is 80π cm3, and resulting hole is given by the volume from the inner radius, 20π cm3. The difference between the two gives the volume of the resulting hollow cylinder, 60π cm3.