Coordinate geometry SAT冲刺4.ppt

1. Polygon 2. Parallelogram 3. diagonal 4. equilateral 5. equiangular 6. quadrilateral 7. interior angle 8. exterior angle Diameter Radius Minor arc 9. substitute 10. pentagon 11. rhombus 12. hexagon 13. rectangle 14. square 15. trapezoid 16. congruence Chord Tangent Major arc Coordinate geometry A coordinate plane is represented by a grid of square boxes that is divided into four quadrants by a horizontal number line, called the x-axis, and a vertical number line, called the y-axis, that intersect at their O point. Each point in the coordinate plane is located by using an ordered pair of numbers, called coordinates, of the (x,y). For example, point P(3,5) is located 3 units to the right of the origin and 5 units above the origin. Finding the distance between two points The distance between two points that do not lie on the same vertical or horizontal line can be determined by plugging the coordinates of the points into the distance formula Finding midpoint of a segment. The coordinates of the midpoint of a segment are one-half the sums of the corresponding coordinates of the endpoints of the segment. Finding the slope of a line Slope is number that represents the steepness of a line. To find the slope of a line, write the change in the y-coordinates of any two points on line over the corresponding change in the x-coordinates of the same two point. Some facts about slope If you know the slope and the coordinates of one point of a line, you can find the coordinates of other points on the same line. For example, if the slope of a line is 2, then for each 1-unit increase in the x-coordinate of a point on this line, the corresponding y-coordinate must increase by 2. So can you find a same point of a line whose slope is 2 and one point is (4,-1)? * Coordinate geometry x-axis y-axis A B If you know the coordinates of points A and B, you can use a formula to find: (1) The distance from A to B (2) The ”slant” or slope of the line that passes through A and B (3) T