SSAT Upper Level Math : Geometry

Study concepts, example questions & explanations for SSAT Upper Level Math

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Example Questions

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.

Possible Answers:

Correct answer:

Explanation:

Below is the figure with the circle and square in question:

Circle on axes

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.

Possible Answers:

Correct answer:

Explanation:

Below is the figure with the circle and square in question:

Circle on axes

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

.

Possible Answers:

Correct answer:

Explanation:

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  ?

Possible Answers:

Correct answer:

Explanation:

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  ?

Possible Answers:

None of the other responses gives the correct answer.

Correct answer:

None of the other responses gives the correct answer.

Explanation:

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 ?

Picture8

Possible Answers:

B

C

A

D

Correct answer:

D

Explanation:

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 ?

Picture1

Possible Answers:

D

C

A

B

Correct answer:

A

Explanation:

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 .

Example Question #313 : Geometry

Which point best represents the coordinate ?

Picture2

Possible Answers:

C

B

A

D

Correct answer:

D

Explanation:

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 , only move up by  on the y-axis. Do not move along the x-axis because the x-coordinate is .

Example Question #1 : How To Graph An Ordered Pair

Which point best represents the coordinate ?

Picture3

Possible Answers:

D

A

C

B

Correct answer:

C

Explanation:

To get to , move right on 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 #2 : How To Graph An Ordered Pair

Which point best represents the coordinate ?

Picture4

Possible Answers:

D

A

C

B

Correct answer:

A

Explanation:

To get to , move left on the x-axis by  then move down 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.

 

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