Bunuel wrote:

The perimeter of the triangle above is

(A) 5√2

(B) 10

(C) 12.5

(D) 15

(E) 25

Attachment:

2017-08-08_2112_003.png

Given \(2\) sides of the triangle have same measure \(= 5\)

Therefore their opposite angle would also be equal.

Let the unknown angles be \(= x\)

\(x + x + 60 = 180\)

\(2x + 60 = 180\)

\(2x = 180 - 60 = 120\)

\(x = \frac{120}{2} = 60\)

Therefore the triangle is equilateral triangle, hence all the sides will be equal.

Perimeter of triangle \(= 5 + 5 + 5 = 15\)

Answer (D)...