How to find the length of a radius - ACT Math
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Circle X is divided into 3 sections: A, B, and C. The 3 sections are equal in area. If the area of section C is 12π, what is the radius of the circle?
Circle X
Circle X is divided into 3 sections: A, B, and C. The 3 sections are equal in area. If the area of section C is 12π, what is the radius of the circle?
Circle X
Find the total area of the circle, then use the area formula to find the radius.
Area of section A = section B = section C
Area of circle X = A + B + C = 12π+ 12π + 12π = 36π
Area of circle = where r is the radius of the circle
36π = πr2
36 = r2
√36 = r
6 = r
Find the total area of the circle, then use the area formula to find the radius.
Area of section A = section B = section C
Area of circle X = A + B + C = 12π+ 12π + 12π = 36π
Area of circle = where r is the radius of the circle
36π = πr2
36 = r2
√36 = r
6 = r
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The specifications of an official NBA basketball are that it must be 29.5 inches in circumference and weigh 22 ounces. What is the approximate radius of the basketball?
The specifications of an official NBA basketball are that it must be 29.5 inches in circumference and weigh 22 ounces. What is the approximate radius of the basketball?
To Find your answer, we would use the formula: C=2πr. We are given that C = 29.5. Thus we can plug in to get \[29.5\]=2πr and then multiply 2π to get 29.5=(6.28)r. Lastly, we divide both sides by 6.28 to get 4.70=r. (The information given of 22 ounces is useless)
To Find your answer, we would use the formula: C=2πr. We are given that C = 29.5. Thus we can plug in to get \[29.5\]=2πr and then multiply 2π to get 29.5=(6.28)r. Lastly, we divide both sides by 6.28 to get 4.70=r. (The information given of 22 ounces is useless)
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A circle with center (8, **–**5) is tangent to the y-axis in the standard (x,y) coordinate plane. What is the radius of this circle?
A circle with center (8, **–**5) is tangent to the y-axis in the standard (x,y) coordinate plane. What is the radius of this circle?
For the circle to be tangent to the y-axis, it must have its outer edge on the axis. The center is 8 units from the edge.
For the circle to be tangent to the y-axis, it must have its outer edge on the axis. The center is 8 units from the edge.
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A circle has an area of 
. What is the radius of the circle, in inches?
A circle has an area of
We know that the formula for the area of a circle is πr_2. Therefore, we must set 49_π equal to this formula to solve for the radius of the circle.
49_π_ = _πr_2
49 = _r_2
7 = r
We know that the formula for the area of a circle is πr_2. Therefore, we must set 49_π equal to this formula to solve for the radius of the circle.
49_π_ = _πr_2
49 = _r_2
7 = r
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A circle has an area of 36π inches. What is the radius of the circle, in inches?
A circle has an area of 36π inches. What is the radius of the circle, in inches?
We know that the formula for the area of a circle is π_r_2. Therefore, we must set 36π equal to this formula to solve for the radius of the circle.
36π = π_r_2
36 = _r_2
6 = r
We know that the formula for the area of a circle is π_r_2. Therefore, we must set 36π equal to this formula to solve for the radius of the circle.
36π = π_r_2
36 = _r_2
6 = r
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A circle has a circumference of 
. What is the radius of the circle, in feet?
A circle has a circumference of
To answer this question we need to find the radius of the circle given the circumference of 
.
The equation for a circle's circumference is:
We can plug our circumference into this equation to find the diameter.
We can now divide both sides by 
So our diameter is 
. To find the radius from the diameter, we use the following equation:
So, for this data:
Therefore, the radius of our circle is 
.
To answer this question we need to find the radius of the circle given the circumference of
The equation for a circle's circumference is:
We can plug our circumference into this equation to find the diameter.
We can now divide both sides by
So our diameter is
So, for this data:
Therefore, the radius of our circle is
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