Introduction to corrdinates

2009-08-22 5:19 am
Find the distance between each of the following pairs of points:

(a) A(7,8),B(12,8)

(b) E(-2,9),F(6,9)

(c) C(-5,-5),D(-5,8)

(d) G(7,9),H(7,23)
更新1:

Given that A(5,3),B(-2,3),C(0,4) and D are the vertices of a rectangle ,find the coordinates of D and the area of the rectangle ABCD.

更新2:

上面的不用理(答下面的) 1 Find the distance between each of the following pairs of points: (a) A(7,8),B(12,8) (b) E(-2,9),F(6,9) (c) C(-5,-5),D(-5,8) (d) G(7,9),H(7,23) 2 Given that A(5,3),B(-2,3),C(0,4) and D are the vertices of a rectangle ,find the coordinates of D and the area of the rectangle ABCD.

回答 (2)

2009-08-22 5:39 am
✔ 最佳答案
a) 12-7= 5units
b) 6-(-2)=8units
c) 8-(-5)=13units
d) 23-9= 14units

actually you can use pyth theorem to calculate if none of the corrdinates are the same a^2+b^2 =c^2
EG a) square root [(7-12)^2+(8-8)^2] = square root 25 = 5

2009-08-21 21:43:54 補充:
2.
since it is rectangle
you can use slope (y1-y2)/(x1-x2) to calculate the slope of BC and the you can know the slope of AD ( they are the same). And similarly find m of AC and you can know the slope of BD. After knowing the 2 slopes, you can find the point D.

D(3,2)
2009-08-22 5:34 am
a)AB=12-7=5//

b) EF=6-(-2)=8//

c) CD=8-(-5)=13//

d) GH=23-9=14//



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