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Triangle ABC is similar to triangle ADE, which is formed with angle A and side AD, as shown.

What could be the coordinates of point E?

(2,–1)
(–1,2)
(–3,–1)
(–1,–3)

Triangle ABC is similar to triangle ADE, which is formed with angle A and side AD-example-1
User Svkvvenky
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2 Answers

2 votes

Answer:

Explanation:

Answer B is correct.

User Jmans
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5.1k points
2 votes

Answer:

Only option B is correct, i.e. (-1, 2).

Explanation:

Two triangles are similar when their corresponding angles are congruent.

Triangle ABC would be similar to triangle ADE when ∠A = ∠A, ∠B = ∠D, and ∠C = ∠E.

Since A is common vertex and D is on side AB, then it is sure that E would be on side AC.

The information ∠B = ∠D, and ∠C = ∠E makes sure that DE║BC.

It means slope of DE = slope of BC.

⇒ (y-3)/(x-2) = (-4+1)/(-5-4)

⇒ (y-3)/(x-2) = (-3)/(-9)

⇒ (y-3)/(x-2) = 1/3

We can try and plug all four options in the proportion and check which one satisfy the equation.

option A: (-1-3)/(2-2) ≠ 1/3

option B: (2-3)/(-1-2) = 1/3

option C: (-1-3)/(-3-2) ≠ 1/3

option D: (-3-3)/(-1-2) ≠ 1/3

Hence, only option B is correct, i.e. (-1, 2).

User Mark F Guerra
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