All SSAT Upper Level Math Resources
Example Questions
Example Question #7 : Circles
What is the equation of a circle that has its center at and has a radius of ?
The general equation of a circle with center and radius is:
Now, plug in the values given by the question:
Example Question #2 : Circles
If the center of a circle with a diameter of 5 is located at , what is the equation of the circle?
Write the formula for the equation of a circle with a given point, .
The radius of the circle is half the diameter, or .
Substitute all the values into the formula and simplify.
Example Question #9 : How To Find The Equation Of A Circle
Give the circumference of the circle on the coordinate plane whose equation is
The standard form of the equation of a circle is
where is the radius of the circle.
We can rewrite the equation we are given, which is in general form, in this standard form as follows:
Complete the squares. Since and , we do this as follows:
, so , and the circumference of the circle is
Example Question #10 : How To Find The Equation Of A Circle
A square on the coordinate plane has as its vertices the points . Give the equation of a circle circumscribed about the square.
Below is the figure with the circle and square in question:
The center of the inscribed circle coincides with that of the square, which is the point . Its diameter is the length of a diagonal of the square, which is times the sidelength 6 of the square - this is . Its radius is, consequently, half this, or . Therefore, in the standard form of the equation,
,
substitute and .
Example Question #311 : Geometry
A square on the coordinate plane has as its vertices the points . Give the equation of a circle inscribed in the square.
Below is the figure with the circle and square in question:
The center of the inscribed circle coincides with that of the square, which is the point . Its diameter is equal to the sidelength of the square, which is 8, so, consequently, its radius is half this, or 4. Therefore, in the standard form of the equation,
,
substitute and .
Example Question #252 : Coordinate Geometry
Give the area of the circle on the coordinate plane whose equation is
.
The standard form of the equation of a circle is
where is the radius of the circle.
We can rewrite the equation we are given, which is in general form, in this standard form as follows:
Complete the squares. Since and , we do this as follows:
, and the area of the circle is
Example Question #253 : Coordinate Geometry
Which of the following is the equation of a circle with center at the origin and area ?
The standard form of the equation of a circle is
,
where the center is and the radius is .
The center of the circle is the origin, so , and the equation is
for some .
The area of the circle is , so
We need go no further; we can substitute to get the equation .
Example Question #11 : Circles
Which of the following is the equation of a circle with center at the origin and circumference ?
None of the other responses gives the correct answer.
None of the other responses gives the correct answer.
The standard form of the equation of a circle is
,
where the center is and the radius is .
The center of the circle is the origin, so .
The equation will be
for some .
The circumference of the circle is , so
The equation is , which is not among the responses.
Example Question #3 : How To Graph An Ordered Pair
Which point best represents the coordinate ?
B
C
A
D
D
To get to , move right along the x-axis by , then move up on the y-axis by .
The sign in front of each number represents which direction to go on the x or y-axis starting at the origin . If the number is positive you go right on the x-axis or up on the y-axis. If the sign is negative then you move to the left on the x-axis or down on the y-axis.
Example Question #312 : Geometry
Which point best represents the coordinates ?
D
C
A
B
A
The sign in front of each number represents which direction to go on the x or y-axis starting at the origin . If the number is positive you go right on the x-axis or up on the y-axis. If the sign is negative then you move to the left on the x-axis or down on the y-axis.
To get to , move left on the x-axis by , then move up on the y-axis by .
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