ACT Math : How to find the radius of a sphere
Study concepts, example questions & explanations for ACT Math
All ACT Math Resources
Example Questions
Example Question #1 :Spheres
The surface area of a sphere is
Solve the equaiton for the surface area of a sphere for the radius and plug in the values:
Example Question #2 :Spheres
What is the radius of a sphere with a volume of
回想一下,sph的体积的方程e is:
For our data, we know:
Solve for
Now, divide out the
Using your calculator, you can solve for
This gives you:
如果你得到something like
Example Question #3 :How To Find The Radius Of A Sphere
The volume of a sphere is
回想一下,sph的体积的方程e is:
For our data, we know:
Solve for
Next, multiply both sides by
Using your calculator, solve for
You should get:
Example Question #4 :How To Find The Radius Of A Sphere
What is the radius of a sphere with a surface area of
Recall that the surface area of a sphere is found by the equation:
For our data, this means:
Solve for
Take the square root of both sides:
Example Question #5 :How To Find The Radius Of A Sphere
What is the radius of a sphere with a volume of
Given the volume of the sphere,
Example Question #6 :How To Find The Radius Of A Sphere
A cube with sides of
Solving this problem requires recognizing that since the cube is circumscribed by the sphere, both solids share the same center. Now it is just a matter of finding the diagonal of the cube, which will double as the diameter of the sphere (by definition, any straight line which passes through the center of the sphere). The formula for the diagonal of a cube is
In this case:
Since the radius is half the diameter, divide the result in half:
All ACT Math Resources
