13. In the rectangular co-ordinate system, a triangle has vertices at (-6,-2), (-4,-6) and (-2,5). What is the area of the triangle?
A. 12 sq units
B. 15 sq units
C. 18 sq units
D. 21 sq units
E. 30 sq units
I dont have the OA for this question.
Hint: complete the rectanlge
co-ordinate geometry
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13. In the rectangular co-ordinate system, a triangle has vertices at (-6,-2), (-4,-6) and (-2,5). What is the area of the triangle?
A. 12 sq units
B. 15 sq units
C. 18 sq units
D. 21 sq units
E. 30 sq units
let the co-ordinates be:
x1, y1
x2, y2 &
x3, y3
so in this problem:
x1= -6, y1 = -2
x2= -4, y2 = -6 &
x3= -2, y3 = 5
Formula; A(triangle having vertices as given above) = 1/2[x1(y2-y3)+x2(y3-y1)+x3(y1-y2)]
= 1/2[-6(-6-5)-4(5+2)-2(-2+6)]
=1/2(66-28-8)
=1/2(30)
=15
So right OA is B. 15 sq. units
A. 12 sq units
B. 15 sq units
C. 18 sq units
D. 21 sq units
E. 30 sq units
let the co-ordinates be:
x1, y1
x2, y2 &
x3, y3
so in this problem:
x1= -6, y1 = -2
x2= -4, y2 = -6 &
x3= -2, y3 = 5
Formula; A(triangle having vertices as given above) = 1/2[x1(y2-y3)+x2(y3-y1)+x3(y1-y2)]
= 1/2[-6(-6-5)-4(5+2)-2(-2+6)]
=1/2(66-28-8)
=1/2(30)
=15
So right OA is B. 15 sq. units