Answer:
We know that the sum of all the interior angles of a triangle is always equal to 180°.
And we know that the angles are in a ratio of:
2:5:5
So if we have an angle (unknown) θ, the angles of this triangle will be written as:
2*θ
5*θ
5*θ
Now remember that the sum of the 3 angles is equal to 180°, this leads to:
2*θ + 5*θ + 5*θ = 180°
Now we can solve this for θ
(2 + 5 + 5)*θ = 180°
12*θ = 180°
θ = 180°/12 = 15°
This means that the angles of this triangle are:
2*θ = 2*15° = 30°
5*θ = 5*15° = 75°
5*θ = 5*15° = 75°
Now we want to classify this triangle based on this, we have two equal angles, which implies that we must have two equal sides and another different side.
Then this is an isosceles triangle.
