Final answer:
A triangle where one angle is equal to the sum of the other two equal angles is a right angled triangle, because the angles sum up to 180 degrees with the two equal angles being 45 degrees each and the third angle 90 degrees. The correct answer is C. Right angled triangle.
Step-by-step explanation:
If one angle of a triangle is equal to the sum of the other two angles which are equal, then the triangle is a/an right angled triangle. This is because the sum of the angles in any triangle adds up to 180 degrees. If we consider the two angles that are equal, let's call each of them x, then their sum is 2x.
According to the question, the third angle is also equal to 2x. So, if we add all three angles together, we get x + x + 2x, which equals 4x. Since we know the total sum of angles in a triangle is 180 degrees, then 4x = 180, hence x = 45. So, the two equal angles are each 45 degrees, and the third angle is 90 degrees, making it a right angled triangle.
The triangle described in the question is a right angled triangle.
In a right angled triangle, one of the angles is equal to 90 degrees. Let's say this angle is x. Given that the sum of the other two angles is equal to x, each of those angles must be 90 - x.
Therefore, the triangle has one angle of 90 degrees and the remaining two angles are equal, making it a right angled triangle.