if the coordinates of the mid point of the sides of a triangle ABC are (1,1),(2,-3),(3,4).find the coordinates of the vertices
Answers
Answer:
coordinates of triangles are let :a (1,1),b (2,-3)andc (3,4)...
then centroid=(x1+x2+x3)/3 and (y1+y2+y3)/3
=(1+2+3)/3, (1-3+4)/3
=6/3,-6/3
=2,-2
Step-by-step explanation:
Answer:
A(x1, y1) = (2, 8)
B(x2, y2) = (-4, -6)
C(x3, y3) = (4, 0)
Step-by-step explanation:
Let the midpoints of sides AB, BC and AC be P, Q and R respectively.
Let co ordinates of A be x1, y1
B be x2, y2
C be x3, y3
By midpont formula (x=x1+x2/2 ,
y=y1+y2/2)
•P(1,1)
1 = (x1 + x2)/2
so, x1 + x2 = 2×1
so, x1 + x2 = 2 ......(1)
1 = (y1 + y2) / 2
so, y1 + y2 = 2 × 1
so, y1 + y2 = 2 ......(2)
•Q(2, -3)
2 = (x2 + x3) / 2
so, x2 + x3 = 2×3
so, x2 + x3 = 6 .......(3)
-3 = (y2 + y3) / 2
so, y2 + y3 = 2*-3
so, y2 + y3 = -6 .......(4)
•R(3, 4)
3 = (x3 + x1) / 2
so, x3 + x1 = 3*2
so, x3 +x1 = 6 ......(5)
4 = (y3 + y1) / 2
so, y3 + y1 = 2*4
so, y3 + y1 = 8 ......(6)
Adding (1), (2) and (3)...
x1+x2+x2+x3+x3+x1 = 2+4+6
so, 2(x1+x2+x3) = 12
so, x1 + x2 + x3 = 12/2
so, x1 + x2 +x3 = 6 ....(7)
Adding (4), (5) and (6)...
y1 + y2 + y2 + y3 + y3 + y1 = 2 + (-6) + 8
so, 2(y1 + y2 + y3) = 4
so, y1 + y2 + y3 = 4/2
so, y1 + y2 + y3 = 2 .....(8)
Substituing (1) in (7)...
x1 + x2 + x3 = 6
so, 2 + x3 = 6
so, x3 = 6 - 2
so, x3 = 4 ...(9)
Substituing (2) in (7)...
x1 + x2 + x3 = 6
so, x1 + 4 = 6
so, x1 = 6 - 4
so, x1 = 2 .... (10)
Substituting (9) and (10) in (7)
x2 + 4 + 6 = 6
so, x2 = 6 - 6 - 4
so, x2 = -4 .....(11)
Similarly
Substituting (4) in (8)....
y1 + y2 + y3 = 2
so, 2 + y3 = 2
so, y3 = 2 - 2
so, y3 = 0 ....(12)
Substituting (5) in (8).....
y1 + y2 + y3 = 2
so, y1 + (-6) = 2
so, y1 = 2 + 6
so, y1 = 8 .....(13)
Substituting (12) and (13) in (8)..
y1 + y2 + y3 = 2
so, 8 + y2 + 0 = 2
so, y2 = 2 - 8
so, y2 = -6 ......(14)
From (9), (10), (11), (12), (13) and (14).....
A(x1, y1) = (2, 8)
B(x2, y2) = (-4, -6)
C(x3, y3) = (4, 0)
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