SAT Math : Geometry

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #531 : Geometry

What is the slope-intercept form of \dpi{100} \small 8x-2y-12=0?

Possible Answers:

\dpi{100} \small y=4x+6

\dpi{100} \small y=4x-6

\dpi{100} \small y=-2x+3

\dpi{100} \small y=2x-3

\dpi{100} \small y=-4x+6

Correct answer:

\dpi{100} \small y=4x-6

Explanation:

The slope intercept form states that \dpi{100} \small y=mx+b. In order to convert the equation to the slope intercept form, isolate \dpi{100} \small y on the left side:

\dpi{100} \small 8x-2y=12

\dpi{100} \small -2y=-8x+12

\dpi{100} \small y=4x-6

Example Question #1441 : Gre Quantitative Reasoning

A line is defined by the following equation:

What is the slope of that line?

Possible Answers:

Correct answer:

Explanation:

The equation of a line is

y=mx + b where m is the slope

Rearrange the equation to match this:

7x + 28y = 84

28y = -7x + 84

y = -(7/28)x + 84/28

y = -(1/4)x + 3

m = -1/4

Example Question #101 : Algebra

If the coordinates (3, 14) and (5, 15) are on the same line, what is the equation of the line?

Possible Answers:

Correct answer:

Explanation:

First solve for the slope of the line, m using y=mx+b

m = (y2 – y1) / (x2 – x1)

= (15  14) / (5 3)

= (1 )/( 8)

=1/8

y = (1/8)x + b

Now, choose one of the coordinates and solve for b:

14 = (1/8)3 + b

14 = 3/8 + b

b = 14 + (3/8)

b = 14.375

y = (1/8)x + 14.375

Example Question #252 : Geometry

What is the equation of a line that passes through coordinates \dpi{100} \small (2,6) and \dpi{100} \small (3,5)?

Possible Answers:

\dpi{100} \small y=-x+8

\dpi{100} \small y=2x+4

\dpi{100} \small y=2x-4

\dpi{100} \small y=3x+2

\dpi{100} \small y=x+7

Correct answer:

\dpi{100} \small y=-x+8

Explanation:

Our first step will be to determing the slope of the line that connects the given points.

Our slope will be . Using slope-intercept form, our equation will be . Use one of the give points in this equation to solve for the y-intercept. We will use \dpi{100} \small (2,6).

Now that we know the y-intercept, we can plug it back into the slope-intercept formula with the slope that we found earlier.

This is our final answer.

Example Question #21 : How To Find The Equation Of A Line

Which of the following equations does NOT represent a line?

Possible Answers:

Correct answer:

Explanation:

The answer is .

A line can only be represented in the form  or , for appropriate constants , , and . A graph must have an equation that can be put into one of these forms to be a line.

 represents a parabola, not a line. Lines will never contain an term.

Example Question #532 : Geometry

Let y = 3x – 6.

At what point does the line above intersect the following:

 

 

Possible Answers:

They do not intersect

(–3,–3)

(–5,6)

They intersect at all points

(0,–1)

Correct answer:

They intersect at all points

Explanation:

If we rearrange the second equation it is the same as the first equation. They are the same line.

Example Question #142 : Lines

Find the equation of a line that goes through the points , and .

Possible Answers:

Correct answer:

Explanation:

For finding the equation of a line, we will be using point-slope form, which is

, where  is the slope, and  is a point. 

We will pick the point 

If we picked the point 

 

We get the same result

Example Question #531 : Sat Mathematics

Find the equation of a line that passes through the point , and is parallel to the line .

Possible Answers:

Correct answer:

Explanation:

Since we want a line that is parallel, we will have the same slope as the line . We can use point slope form to create an equation.

, where  is the slope and  is a point.

Example Question #23 : Slope And Line Equations

Find the equation of the line shown in the graph below:

 

 Sat_math_164_05

 
Possible Answers:

y = -1/2x - 4

y = x/2 + 4

 y = -1/2x + 4

y = 2x + 4

Correct answer:

y = x/2 + 4

Explanation:

Based on the graph the y-intercept is 4. So we can eliminate choice y = x/2 - 4.

The graph is rising to the right which means our slope is positive, so we can eliminate choice y = -1/2x + 4.

Based on the line, if we start at (0,4) and go up 1 then 2 to the right we will be back on the line, meaning we have a slope of  (1/2).

Using the slope intercept formula we can plug in y= (1/2)x + 4.

 

 

Example Question #1 : Distance Formula

What is the distance between (1, 4) and (5, 1)?

Possible Answers:

5

3

7

9

4

Correct answer:

5

Explanation:

Let P1 = (1, 4) and P2 = (5, 1)

Substitute these values into the distance formula: 

Actmath_29_372_q6_1_copy

The distance formula is an application of the Pythagorean Theorem:  a2 + b2 = c2

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