SAT Math : Diameter

Study concepts, example questions & explanations for SAT Math

varsity tutors app store varsity tutors android store varsity tutors amazon store varsity tutors ibooks store

Example Questions

2 Next →

Example Question #41 : Circles

The area of a circle is . Find the diameter. 

Possible Answers:

Correct answer:

Explanation:

The formula for the area of a circle is

with r being the length of the radius.

Since we know that the area of the circle is

we can solve for r and get 12. (Do so by canceling out the two pi's and taking the square root of 144). Once we know the radius, we can easily find the diameter, since the diameter is twice the length of the radius. Therefore, the diameter is 24, as

Example Question #51 : Circles

Give the diameter of a circle with radius forty-two inches.

Possible Answers:

None of these

Correct answer:

Explanation:

The diameter of a circle is twice its radius, so if a circle has radius 42 inches, its diameter is 

 

Divide by 12 to convert to feet:

Example Question #291 : Plane Geometry

Let  represent the area of a circle and  represent its circumference. Which of the following equations expresses  in terms of

Possible Answers:


Correct answer:

Explanation:

The formula for the area of a circle is , and the formula for circumference is . If we solve for C in terms of r, we get
.

We can then substitute this value of r into the formula for the area:

 

2 Next →
Learning Tools by Varsity Tutors