Pearson Geometry Common Core, 2011
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Pearson Geometry Common Core, 2011 View details
5. Circles in the Coordinate Plane
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Exercise 48 Page 802

Graph the circle and the line in order to find the points of intersection.

Graph:

Points of intersection: (2,3),(3,2)

Practice makes perfect

By graphing the given equations, we can determine the number of points of intersection between the circle and the line. To do so, we need to graph both figures. Let's consider one of them at a time.

Graphing the Circle

Let's start by recalling the standard equation of a circle. (x- h)^2+(y- k)^2= r^2 Here, the center is the point ( h, k) and the radius is r. We will rewrite the given equation to match this form, and then we can identify the center and the radius.

x^2+y^2=13 ⇕ (x- 0)^2+(y- 0)^2=( sqrt(13))^2 The center of the circle is the point ( 0, 0), and its radius is sqrt(13). We can graph the circle using this information.

Graphing the Line

To graph the line, we will need its equation to be in slope-intercept form to help us identify the slope m and y-intercept b. Let's rewrite the equation in slope-intercept form, highlighting the m and b value.

Given Equation Slope-Intercept Form Slope m y-intercept b
y=-x+5 y=-1x+ 5 -1 (0, 5)

To graph this equation, we will start by plotting its y-intercept. Then, we will use the slope to determine another point that satisfies the equation, and connect the points with a line.

Finding the Points of Intersection

We can see that the circle and the line intersect at exactly two points. Let's identify them.

The points of intersection are (2,3) and (3,2).