SSAT Upper Level Math : Coordinate Geometry

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

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Example Questions

Example Question #331 : Coordinate Geometry

What are the coordinates for point L?

Graph11

Possible Answers:

\displaystyle (5, 2)

\displaystyle (2, -5)

\displaystyle (2, 5)

\displaystyle (-5, 2)

Correct answer:

\displaystyle (2, -5)

Explanation:

Find the x-coordinate by going right on the horizontal x-axis until you come across the line that is directly above the point. The x-coordinate is \displaystyle 2.

Now, continue down until you reach the point and look across to the vertical y-axis. The y-coordinate is \displaystyle -5.

\displaystyle (2, -5) are the coordinates for point L.

Example Question #601 : Ssat Upper Level Quantitative (Math)

What are the coordinates for point M?

Graph12

Possible Answers:

\displaystyle (-7, -4)

\displaystyle (-4, 7)

\displaystyle (7, 4)

\displaystyle (4, 7)

Correct answer:

\displaystyle (7, 4)

Explanation:

Find the x-coordinate by going right on the horizontal x-axis until you come across the line that is directly under the point. The x-coordinate is \displaystyle 7.

Now, continue up until you reach the point and look across to the vertical y-axis. The y-coordinate is \displaystyle 4.

\displaystyle (7, 4) are the coordinates for point M.

Example Question #602 : Ssat Upper Level Quantitative (Math)

What are the coordinates for point K?

Graph10

Possible Answers:

\displaystyle (6, 3)

\displaystyle (-6, 3)

\displaystyle (-3, -6)

\displaystyle (-6, -3)

Correct answer:

\displaystyle (-6, -3)

Explanation:

Find the x-coordinate by going left on the horizontal x-axis until you come across the line that is above the point. The x-coordinate is \displaystyle -6.

Now, continue down until you reach the point and look across to the vertical y-axis. The y-coordinate is \displaystyle -3.

\displaystyle (-6, -3) are the coordinates for point K.

Example Question #1 : Graphing Functions

Line

Refer to the above red line. A line is drawn perpendicular to that line, and with the same \displaystyle y-intercept.  Give the equation of that line in slope-intercept form.

Possible Answers:

\displaystyle y = - \frac{1}{2}x + 4

\displaystyle y = \frac{1}{2}x + 4

\displaystyle y = \frac{1}{2}x - 4

\displaystyle y = \frac{1}{2}x + 8

\displaystyle y = - \frac{1}{2}x + 8

Correct answer:

\displaystyle y = - \frac{1}{2}x + 8

Explanation:

First, we need to find the slope of the above line. 

The slope of a line. given two points \displaystyle (x_{1}, y_{1}), (x_{2}, y_{2}) can be calculated using the slope formula

\displaystyle m = \frac{y_{2}-y_{1}}{x_{2}-x _{1}}

Set \displaystyle x_{1}=-4, y_{1}=x_{2}= 0, y_{2}=8:

\displaystyle m = \frac{8-0}{0-(-4)} = \frac{8}{4} = 2

 

The slope of a line perpendicular to it has as its slope the opposite of the reciprocal of 2, which would be \displaystyle m = -\frac{1}{2}. Since we want this line to have the same \displaystyle y-intercept as the first line, which is the point \displaystyle (0,8), we can substitute \displaystyle m = -\frac{1}{2} and \displaystyle b = 8 in the slope-intercept form:

\displaystyle y = mx + b

\displaystyle y = - \frac{1}{2}x + 8

Example Question #2 : How To Graph A Function

Axes

Refer to the above diagram. If the red line passes through the point \displaystyle \left ( N, 4\right ), what is the value of \displaystyle N?

Possible Answers:

\displaystyle N = -5

\displaystyle N= -1\frac{1}{3}

\displaystyle N = -3\frac{1}{3}

\displaystyle N = -7\frac{1}{3}

\displaystyle N = -4\frac{2}{3}

Correct answer:

\displaystyle N = -4\frac{2}{3}

Explanation:

One way to answer this is to first find the equation of the line. 

The slope of a line. given two points \displaystyle (x_{1}, y_{1}), (x_{2}, y_{2}) can be calculated using the slope formula

\displaystyle m = \frac{y_{2}-y_{1}}{x_{2}-x _{1}}

Set \displaystyle x_{1}=-6, y_{1}=x_{2}= 0, y_{2}=18:

\displaystyle m = \frac{18-0}{0-(-6)} = \frac{18}{6} = 3

The line has slope 3 and \displaystyle y-intercept \displaystyle (0,18), so we can substitute \displaystyle m = 3, b = 18 in the slope-intercept form:

\displaystyle y = mx+b

\displaystyle y = 3x+18

Now substitute 4 for \displaystyle y and \displaystyle N for \displaystyle x and solve for \displaystyle N:

\displaystyle 4= 3N+18

\displaystyle -14 =3N

\displaystyle N = -\frac{14}{3}= -4\frac{2}{3}

Example Question #1 : How To Graph Complex Numbers

Multiply:

\displaystyle \left (7 - 2i \right )\left (7 - 3i \right )

Possible Answers:

\displaystyle 55 +7i

\displaystyle 49 + 6i

\displaystyle 55 -35i

\displaystyle 43 -35i

\displaystyle 43 -7i

Correct answer:

\displaystyle 43 -35i

Explanation:

FOIL the product out:

\displaystyle \left (7 - 2i \right )\left (7 - 3i \right )

\displaystyle = 7 \cdot 7 - 7 \cdot 3i - 7 \cdot 2i + 2i \cdot 3i

\displaystyle = 49 -21i - 14i + 6 i^{2}

\displaystyle = 49 -21i - 14i + 6 (-1)

\displaystyle = 49 -6 -21i - 14i

\displaystyle = 43 -35i

Example Question #1 : How To Graph Complex Numbers

Simplify:

\displaystyle \left ( 8 - 3i\right ) ^{2}

Possible Answers:

\displaystyle 73

\displaystyle 73- 48i

\displaystyle 55

\displaystyle 55 - 48i

\displaystyle 55 +48i

Correct answer:

\displaystyle 55 - 48i

Explanation:

Use the square of a binomial pattern to multiply this:

\displaystyle \left ( 8 - 3i\right ) ^{2}

\displaystyle = 8 ^{2}- 2 \cdot8\cdot3i + \left ( 3i\right )^{2}

\displaystyle = 64- 48i + 3^{2}i^{2}

\displaystyle = 64- 48i + 9 (-1)

\displaystyle = 64-9 - 48i

\displaystyle = 55 - 48i

Example Question #391 : Geometry

Multiply:

\displaystyle (1.1 + 0.6i )(1.1 - 0.6i )

Possible Answers:

\displaystyle 1.57

\displaystyle 1.57 - 1.32i

\displaystyle 0.85 + 1.32i

\displaystyle 1.21 - 0.36i

\displaystyle 0.85

Correct answer:

\displaystyle 1.57

Explanation:

This is a product of an imaginary number and its complex conjugate, so it can be evaluated using this formula:

\displaystyle \left (a + bi \right )\left (a -bi \right ) = a^{2} + b ^{2}

\displaystyle \left (1.1 + 0.6i \right )\left (1.1 -0.6 i \right ) = 1.1^{2} + 0.6 ^{2} = 1.21 + 0.36 = 1.57

Example Question #613 : Ssat Upper Level Quantitative (Math)

Multiply:

\displaystyle \left (5 - 3i \right )\left (5 +3i \right )

Possible Answers:

\displaystyle 25 -9i

\displaystyle 34

\displaystyle 34 +30i

\displaystyle 16 -30i

\displaystyle 16

Correct answer:

\displaystyle 34

Explanation:

This is a product of an imaginary number and its complex conjugate, so it can be evaluated using this formula:

\displaystyle \left (a - bi \right )\left (a +bi \right ) = a^{2} + b ^{2}

\displaystyle \left (5 - 3i \right )\left (5 +3i \right ) = 5 ^{2} + 3 ^{2}= 25 + 9 = 34

Example Question #5 : How To Graph Complex Numbers

Define an operation \displaystyle * as follows:

For all complex numbers \displaystyle a,b,

\displaystyle a*b = a ^{5}-b^{3}

Evaluate \displaystyle \left (2 i \right )* \left (3i \right )

Possible Answers:

\displaystyle 5i

\displaystyle -27+32i

\displaystyle 27 -32i

\displaystyle 32 - 27i

\displaystyle 59i

Correct answer:

\displaystyle 59i

Explanation:

\displaystyle a*b = a ^{5}-b^{3}

\displaystyle \left (2 i \right )* \left (3i \right ) = \left (2 i \right ) ^{5}-\left (3i \right ) ^{3}

\displaystyle = 2^{5} i^{5} - 3^{3} i ^{3}

\displaystyle = 32\cdot i^{4} \cdot i - 27 \cdot (-i )

\displaystyle = 32\cdot 1 \cdot i +27 i

\displaystyle = 32 i +27 i

\displaystyle = 59 i

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