In a triangle ABC, the three angles are x, y, and y + 10. Also, 2x − 4y = 20°. Which type of triangle is ABC?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. Right-angled.
Given that
The 3 angles of the triangle are = x, y, and y + 10
We know that the sum of the interior angles of a triangle is 180º
Hence, x + y + y + 10 = 180º
⇒ x + 2y = 170º
Also, it is given that
2x − 4y = 20°
Solving the 2 equations we get
4y = 160º
y = 40º
Hence, x = 90º
Hence, the triangle is right-angled.